Patent ID: 12211904

DETAILED DESCRIPTION

Reference will now be made in detail to embodiments, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. In this regard, the present embodiments may have different forms and should not be construed as being limited to the descriptions set forth herein. Accordingly, the embodiments are merely described below, by referring to the figures, to explain aspects. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. Expressions such as “at least one of,” when preceding a list of elements, modify the entire list of elements and do not modify the individual elements of the list.

Hereinafter, example embodiments will be described with reference to the accompanying drawings. In the drawings, like reference numerals refer to like elements, and the sizes of elements may be exaggerated for clarity of illustration. The embodiments described herein are for illustrative purposes only, and various modifications may be made therein.

In the following description, when an element is referred to as being “above” or “on” another element, it may be directly on an upper, lower, left, or right side of the other element while making contact with the other element or may be above an upper, lower, left, or right side of the other element without making contact with the other element. The terms of a singular form may include plural forms unless otherwise mentioned. It will be further understood that the terms “comprises” and/or “comprising” used herein specify the presence of stated features or elements, but do not preclude the presence or addition of one or more other features or elements.

An element referred to with the definite article or a demonstrative pronoun may be construed as the element or the elements even though it has a singular form. Operations of a method may be performed in an appropriate order unless explicitly described in terms of order or described to the contrary, and are not limited to the stated order thereof.

In the present disclosure, terms such as “unit” or “module” may be used to denote a unit that has at least one function or operation and is implemented with hardware, software, or a combination of hardware and software.

When the terms “about” or “substantially” are used in this specification in connection with a numerical value, it is intended that the associated numerical value includes a manufacturing or operational tolerance (e.g., ±10%) around the stated numerical value. Moreover, when the words “generally” and “substantially” are used in connection with geometric shapes, it is intended that precision of the geometric shape is not required but that latitude for the shape is within the scope of the disclosure. Further, regardless of whether numerical values or shapes are modified as “about” or “substantially,” it will be understood that these values and shapes should be construed as including a manufacturing or operational tolerance (e.g., ±10%) around the stated numerical values or shapes.

Furthermore, line connections or connection members between elements depicted in the drawings represent functional connections and/or physical or circuit connections by way of example, and in actual applications, they may be replaced or embodied with various additional functional connections, physical connections, or circuit connections.

Examples are just used herein to describe technical ideas and should not be considered for purposes of limitation unless defined by the claims.

FIG.1is a cross-sectional view illustrating a black phosphorus (BP)-two dimensional (2D) material complex100according to an example embodiment.

Referring toFIG.1, the BP-2D material complex100includes: first and second 2D material layers121and122; and a BP sheet130provided between the first and second 2D material layers121and122. Here, the BP sheet130may be encapsulated by the first and second 2D material layers121and122.

The first 2D material layer121may be provided on an upper surface of a substrate110. The substrate110may be selected from substrates including various materials such as a semiconductor substrate or an insulating substrate. The first 2D material layer121may include a material having a 2D crystal structure in which constituent atoms are planarly bonded. For example, the first 2D material layer121may include a 2D material that is different from the material of the BP sheet130. The first 2D material layer121may be formed on the upper surface of the substrate110such that the first 2D material layer121may be coupled to the upper surface of the substrate110by van der Waals force.

The first 2D material layer121may have a single-layer structure or a multilayer structure. For example, the first 2D material layer121may have a thickness of about 10 nm or less.FIG.1illustrates an example in which the first 2D material layer121has a single-layer structure. When the first 2D material layer121has a multilayer structure, stacked layers of the multilayer structure may be coupled to each other by van der Waals force.

The first 2D material layer121may include, for example, graphene, which is a conductive 2D material. Graphene is a 2D material having a hexagonal honeycomb structure in which carbon atoms are covalently bonded in a 2D manner.

When the first 2D material layer121includes single-layer graphene, the first 2D material layer121may have a thickness of about 0.34 nm. In addition, when the first 2D material layer121includes multilayer graphene, the distance between stacked layers may be, for example, about 0.34 nm. Here, the distance between layers refers to the distance between the centers of the layers.

The first 2D material layer121may include, for example, hexagonal-boron nitride (h-BN), which is an insulating 2D material. Alternatively, the first 2D material layer121may include, for example, a transition metal dichalcogenide (TMD), which is a 2D material having semiconductor characteristics.

TMD is a 2D material having high thermal stability, high mechanical strength, and high thermal conductivity. For example, TMD may include: one selected from the group consisting of molybdenum (Mo), tungsten (W), niobium (Nb), vanadium (V), tantalum (Ta), titanium (Ti), zirconium (Zr), hafnium (Hf), technetium (Tc), rhenium (Re), copper (Cu), gallium (Ga), indium (In), tin (Sn), germanium (Ge), and lead (Pb); and a chalcogen selected from the group consisting of sulfur (S), selenium (Se), and tellurium (Te). However, the listed elements are merely examples, and another material may be used as TMD.

The BP sheet130is provided on an upper surface of the first 2D material layer121. Here, the BP sheet130provided on the first 2D material layer121may have an area equal to or smaller than the area of the first 2D material layer121. That is, the BP sheet130may not protrude from an outer portion of the first 2D material layer121.

The BP sheet130is a 2D material having a 2D crystal structure (for example, a corrugated honeycomb structure) in which phosphorus atoms are covalently bonded. The BP sheet130may have a single-layer structure or a multilayer structure.FIG.1illustrates an example in which the BP sheet130has a single-layer structure. However, as described later, the BP sheet130may have a multilayer structure. The BP sheet130may include, for example, one to fifty layers. In this case, the BP sheet130may have a thickness of about 10 nm or less.

When the BP sheet130has a single-layer structure, the BP sheet130may have a thickness (t) of about 0.5 nm. The BP sheet130may be coupled to the first 2D material layer121by van der Waals force. The distance d1between the first 2D material layer121and the BP sheet130may be, for example, about 0.8 nm or less. Here, the distance d1between the first 2D material layer121and the BP sheet130refers to the distance between the center of the first 2D material layer121and the center of the BP sheet130.

The second 2D material layer122is provided on an upper surface of the BP sheet130. Like the first 2D material layer121, the second 2D material layer122may include a material having a 2D crystal structure in which constituent atoms are planarly bonded. The second 2D material layer122may include a 2D material that is different from the material of the BP sheet130.

The second 2D material layer122may have a single-layer structure or a multilayer structure. For example, the second 2D material layer122may have a thickness of about 10 nm or less.FIG.1illustrates an example in which the second 2D material layer122has a single-layer structure. When the second 2D material layer122has a multilayer structure, stacked layers of the multilayer structure may be coupled to each other by van der Waals force.

The second 2D material layer122may include, for example, graphene, h-BN, or TMD. The second 2D material layer122may include the same material as the first 2D material layer121. For example, both the first and second 2D material layers121and122may include graphene or h-BN. Alternatively, the second 2D material layer122may include a material that is different from the material of the first 2D material layer121. For example, the first 2D material layer121may include h-BN, and the second 2D material layer122may include graphene. However, this is merely an example.

The second 2D material layer122may have an area equal to or larger than the area of the BP sheet130. That is, the second 2D material layer122may entirely cover the BP sheet130. Therefore, the BP sheet130may not protrude from an outer portion of the second 2D material layer122. The outer portion of the first 2D material layer121and the outer portion of the second 2D material layer122which are around the BP sheet130may be coupled to each other by van der Waals force. As described above, the BP sheet130is provided between the first and second 2D material layers121and122of which the outer portions are coupled to each other by the van der Waals force, and thus, the BP sheets130may be encapsulated by the first and second 2D material layers121and122.

The second 2D material layer122provided on the BP sheet130may be coupled to the BP sheet130by van der Waals force. Here, the distance d2between the second 2D material layer122and the BP sheet130may be, for example, about 0.8 nm or less. The distance d2between the second 2D material layer122and the BP sheet130refers to the distance between the center of the second 2D material layer122and the center of the BP sheet130.

In the BP-2D material complex100of the example embodiment, the BP sheet130is provided between the first and second 2D material layers121and122, which are coupled to each other by van der Waals force such that the BP sheet130may be protected from external environments such as oxidation. In addition, the BP sheet130has semiconductor characteristics, high charge mobility, and a high on/off current ratio, and thus, the BP-2D material complex100of the example embodiment may be applied to various electronic devices such as field effect transistors (FETs) or photodetectors.

FIG.2is a cross-sectional view illustrating a BP-2D material complex200according to another example embodiment. The BP-2D material complex200shown inFIG.2is the same as the BP-2D material complex100shown inFIG.1except that a BP sheet230has a multilayer structure.

Referring toFIG.2, the BP sheet230includes a first layer231and a second layer232, which are vertically stacked. Here, the distance d3between the first layer231and the second layer232may be about 0.5 nm. The distance d3between the first layer231and the second layer232refers to the distance between the center of the first layer231and the center of the second layer232. The case in which the BP sheet230includes two layers, that is, the first and second layers231and232, has been described. However, the present disclosure is not limited thereto, and the BP sheet230may include various numbers of layers. For example, the BP sheet230may include one to fifty layers. In this case, the BP sheet230may have a thickness of about 10 nm or less.

FIG.3is a cross-sectional view illustrating a BP-2D material complex300according to another example embodiment. Hereinafter, differences from the above-described embodiments will be mainly described.

Referring toFIG.3, the BP-2D material complex300includes a substrate110, a 2D material layer320, and a BP sheet330provided between the substrate110and the 2D material layer320. In the present example embodiment, the BP sheet330may be encapsulated by the substrate110and the 2D material layer320.

A substrate selected from substrates formed of various materials may be used as the substrate110. The BP sheet330is provided on an upper surface of the substrate110. Because BP sheets have been described, a detailed description of the BP sheet330will be omitted. The BP sheet330may have an area smaller than the area of the upper surface of the substrate110. Therefore, the BP sheet330may not be provided on an outer portion of the upper surface of the substrate110.

The BP sheet330may have a single-layer structure or a multi-layer structure. The BP sheet330may include, for example, one to fifty layers. In this case, the BP sheet330may have a thickness of about 10 nm or less.

The 2D material layer320is provided on an upper surface of the BP sheet330. The 2D material layer320may include a 2D material that is different from the material of the BP sheet330. The 2D material layer320may include, for example, graphene, h-BN, or TMD. Because the 2D material layer320is the same as the first and second 2D material layers121and122described above, a description thereof will be omitted.

The 2D material layer320may have an area equal to or larger than the area of the BP sheet330. That is, the 2D material layer320may entirely cover the BP sheet330. Therefore, the BP sheet330may not protrude from an outer portion of the 2D material layer320. Here, the outer portion of the substrate110around the BP sheet330and the outer portion of the 2D material layer320around the BP sheet330may be coupled to each other by van der Waals force. As described above, because the BP sheet330is provided between the substrate110and the 2D material layer320of which the outer portions are coupled to each other by van der Waals force, the BP sheet330may be encapsulated by the substrate110and the 2D material layer320.

The 2D material layer320provided on the BP sheet330may be coupled to the BP sheet330by van der Waals force. Here, the distance between the 2D material layer320and the BP sheet330may be, for example, about 0.8 nm or less.

FIGS.4to9are views illustrating a method of manufacturing a BP-2D material complex, according to an example embodiment.

Referring toFIG.4, a first 2D material layer121is formed on an upper surface of a substrate110. A substrate selected from substrates including various materials such as a semiconductor substrate or an insulating substrate may be used as the substrate110. The first 2D material layer121may include a material having a 2D crystal structure in which constituent atoms are planarly bonded. For example, the first 2D material layer121may include a 2D material that is different from the material of a BP sheet130(described later).

The first 2D material layer121may be formed on the upper surface of the substrate110by, for example, a transfer method. However, this is a non-limiting example. When the first 2D material layer121is formed on the upper surface of the substrate110as described above, the first 2D material layer121may be coupled to the upper surface of the substrate110by van der Waals force.

The first 2D material layer121may have a single-layer structure or a multilayer structure. For example, the first 2D material layer121may have a thickness of about 10 nm or less.FIG.4illustrates an example in which the first 2D material layer121has a single-layer structure. When the first 2D material layer121has a multilayer structure, stacked layers of the multilayer structure may be coupled to each other by van der Waals force.

The first 2D material layer121may include, for example, graphene, which is a conductive 2D material. When the first 2D material layer121includes single-layer graphene, the first 2D material layer121may have a thickness of about 0.34 nm. In addition, when the first 2D material layer121includes multilayer graphene, the distance between stacked layers may be, for example, about 0.34 nm.

The first 2D material layer121may include, for example, h-BN, which is an insulating 2D material. Alternatively, the first 2D material layer121may include, for example, TMD, which is a 2D material having semiconductor characteristics.

Referring toFIG.5, a BP precursor film135is formed on an upper surface of the first 2D material layer121. For example, the BP precursor film135may have a thickness of about 10 nm or less. The BP precursor film135may include, for example, white phosphorus (WP), red phosphorus (RP), phosphorus triiodide (PI3), or phosphorus trichloride (PCl3).

For example, the BP precursor film135may be formed by coating the upper surface of the first 2D material layer121with a solution containing PI3or PCl3and then reducing the solution to form a red phosphorus film. Alternatively, the BP precursor film135may be formed on the upper surface of the first 2D material layer121through a vapor deposition process using white phosphorus (WP) or red phosphorus (RP).

The BP precursor film135provided on the first 2D material layer121may have an area equal to or smaller than the area of the first 2D material layer121. The BP precursor film135may not protrude from an outer portion of the first 2D material layer121.

Referring toFIG.6, a second 2D material layer122is formed on the BP precursor film135. The second 2D material layer122may be formed on the first 2D material layer121by, for example, a transfer method, such that the second 2D material layer122may cover the BP precursor film135. Like the first 2D material layer121, the second 2D material layer122may include a material having a 2D crystal structure in which constituent atoms are planarly bonded. The second 2D material layer122may include a 2D material that is different from the material of the BP sheet130.

The second 2D material layer122may have a single-layer structure or a multilayer structure. For example, the second 2D material layer122may have a thickness of about 10 nm or less.FIG.6illustrates an example in which the second 2D material layer122has a single-layer structure. When the second 2D material layer122has a multilayer structure, stacked layers of the multilayer structure may be coupled to each other by van der Waals force.

The second 2D material layer122may include, for example, graphene, h-BN, or TMD. The second 2D material layer122may include the same material as the first 2D material layer121. For example, both the first and second 2D material layers121and122may include graphene or h-BN. Alternatively, the second 2D material layer122may include a material that is different from the material of the first 2D material layer121. For example, the first 2D material layer121may include h-BN, and the second 2D material layer122may include graphene. However, this is merely an example.

The second 2D material layer122may have an area equal to or larger than the area of the BP precursor film135. That is, the second 2D material layer122may entirely cover the BP precursor film135. Therefore, the BP precursor film135may not protrude from an outer portion of the second 2D material layer121. The outer portion of the first 2D material layer121around the BP precursor film135and the outer portion of the second 2D material layer122around the BP precursor film135may be coupled to each other by van der Waals force. Therefore, the BP precursor film135may be encapsulated by the first and second 2D material layers121and122.

Referring toFIG.7, as pressure and heat are applied to the BP precursor film135in the state shown inFIG.6, the BP precursor film135is converted into the BP sheet130, thereby forming a BP-2D material complex100as shown inFIG.8.

As described above, the BP sheet130includes a 2D semiconductor material having a 2D crystal structure, for example, a corrugated honeycomb structure, in which phosphorus atoms are covalently bonded. In general, BP may be formed by heating white phosphorus or red phosphorus which is a precursor material at a high pressure (for example, at about 1.2 GPa). In the present example embodiment, however, the BP sheet130may be formed at a relatively low pressure such as atmospheric pressure.

For example, as shown inFIG.6, the BP precursor film135is formed between the first and second 2D material layers121and122, which are coupled to each other by van der Waals force. In this state, a great van der Waals pressure formed between the first and second 2D material layers121and122may be applied to the BP precursor film135. For example, when both the first and second 2D material layers121and122include graphene, the van der Waals pressure formed between the first and second 2D material layers121and122may be about 1.0 GPa.

As described above, in a state in which a great van der Waals pressure formed by the first and second 2D material layers121and122is applied to the BP precursor film135, the BP precursor film135may be converted into the BP sheet130even at a relatively low pressure such as atmospheric pressure. For example, the pressure applied to the BP precursor film135may be, for example, about 400 MPa or less. For example, the pressure applied to the BP precursor film135may be about 0.1 MPa to 200 MPa.

In addition, the temperature to which the BP precursor film135is heated is, for example, about 700° C. or less. The temperature of 700° C. or less refers to temperature of the process chamber for heating the black phosphorous precursor film. For example, the temperature, to which the BP precursor film135is heated, may be about 200° C. to about 600° C.

As described above, when the BP precursor film135formed between the first and second 2D material layers121and122, which are coupled to each other by van der Waals force, is compressed and heated to a pressure of about 400 MPa or less and a temperature of about 700° C. or less, the BP precursor film135may be converted into the BP sheet130. Here, the BP sheet130may have a single-layer structure or a multilayer structure depending on the thickness of the BP precursor film135.

FIG.8illustrates an example in which the BP sheet130has a single-layer structure, and in the case, the BP sheet130may have a thickness t of about 0.5 nm. However, the BP sheet130may have a multilayer structure. For example, the BP sheet130may include, for example, one to fifty layers. In this case, the BP sheet130may have a thickness of about 10 nm or less.

In the BP-2D material complex100, the BP sheet130is coupled to both the first and second 2D material layers121and122by van der Waals force. In this case, the distance from the BP sheet130to each of the first and second 2D material layers121and122may be about 0.8 nm or less.

Referring toFIG.9, the BP-2D material complex100may be patterned in a desired and/or alternatively predetermined shape.FIG.9shows a state in which outer portions of the first and second 2D material layers121and122are removed to expose both sides of the BP sheet130. The structure shown inFIG.9may be applied to electronic devices such as FETs as described later.

As described above, in the present example embodiment, the BP precursor film135may be converted into the BP sheet130even at a relatively low pressure such as atmospheric pressure by using van der Waals pressure formed between the first and second 2D material layers121and122. Therefore, the BP sheet130and the BP-2D material complex100including the BP sheet130may be easily manufactured.

Furthermore, in the process of converting the BP precursor film135into the BP sheet130, BP may epitaxially grow depending on the crystal orientations of the first and second 2D material layers121and122, and thus, the BP sheet130may have a constant charge mobility.

FIG.10Aillustrates a Raman spectrum of the BP-2D material complex100prepared by the method described with reference toFIGS.4to9.FIG.10Bis an enlarged view illustrating a region A ofFIG.10A. Here, graphene was used as both the first and second 2D material layers121and122.

Referring toFIGS.10A and10B, the D peak, G peak, and 2D peak indicate the presence of graphene, and the A1gpeak, B2gpeak, and A2gpeak indicate the presence of BP. Therefore, it may be ascertained that a BP sheet was formed between graphene layers by the method described with reference toFIGS.4to9.

FIGS.11to15are views illustrating a method of manufacturing a BP-2D material complex, according to another example embodiment.

Referring toFIG.11, a substrate110is prepared. Then, a BP precursor film335is formed on an upper surface of the substrate110. A substrate selected from substrates including various materials may be used as the substrate110. For example, the BP precursor film335may have a thickness of about 10 nm or less.

The BP precursor film335may include, for example, white phosphorus (WP), red phosphorus (RP), PI3, or PCl3. The BP precursor film335may be formed by coating the upper surface of the substrate110with a solution containing PIs or PCIS and then reducing the solution to form a red phosphorus layer. Alternatively, the BP precursor film335may be formed on the upper surface of the substrate110through a vapor deposition process using white phosphorus or red phosphorus.

The BP precursor film335may have an area equal to or smaller than the area of the upper surface of the substrate110. The BP precursor film335may not be formed on an outer portion of the upper surface of the substrate110.

Referring toFIG.12, a 2D material layer320is formed on the BP precursor film335. The 2D material layer320may be formed by, for example, a transfer method, on the upper surface of the substrate110to cover the BP precursor film335. The 2D material layer320may include a 2D material that is different from the material of a BP sheet330(described later). The 2D material layer320may include, for example, graphene, h-BN, or TMD.

The 2D material layer320may have a single-layer structure or a multi-layer structure. For example, the 2D material layer320may have a thickness of about 10 nm or less. When the 2D material layer320has a multilayer structure, stacked layers of the multilayer structure may be coupled to each other by van der Waals force.

The 2D material layer320may have an area equal to or larger than the area of the BP precursor film335. That is, the 2D material layer320may entirely cover the BP precursor film335. Therefore, the BP precursor film335may not protrude from an outer portion of the 2D material layer320. The outer portion of the substrate110around the BP precursor film335and the outer portion of the 2D material layer320around the BP precursor film335may be coupled to each other by van der Waals force. Therefore, the BP precursor film335may be encapsulated by the substrate110and the 2D material layer320.

Referring toFIG.13, as pressure and heat are applied to the BP precursor film335in the state shown inFIG.12, the BP precursor film335is converted into the BP sheet330, thereby forming a BP-2D material complex300as shown inFIG.14.

As described above, the BP precursor film335is formed between the substrate110and the 2D material layer320, which are coupled to each other by van der Waals force. In this state, a great van der Waals pressure formed between the substrate110and the 2D material layer320may be applied to the BP precursor film335. In the state in which a great van der Waals pressure formed by the substrate110and the 2D material layer320is applied to the BP precursor film335, the BP precursor film335may be converted into the BP sheet330even at a relatively low pressure such as atmospheric pressure. For example, the pressure applied to the BP precursor film335may be, for example, about 400 MPa or less. For example, the pressure applied to the BP precursor film335may be about 0.1 MPa to about 200 MPa.

The BP precursor film335may be heated to a temperature of, for example, about 700° C. or less. For example, the BP precursor film335may be heated to about 200° C. to about 600° C.

The BP sheet330may have a single-layer structure or a multilayer structure depending on the thickness of the BP precursor film335. For example, the BP sheet330may include, for example, one to fifty layers. In this case, the BP sheet330may have a thickness of about 10 nm or less. In the BP-2D material complex300, the BP sheet330is coupled to the 2D material layer320by van der Waals force. In this case, the distance between the BP sheet330and the 2D material layer320may be about 0.8 nm or less.

Referring toFIG.15, the BP-2D material complex300may be patterned in a desired and/or alternatively predetermined shape.FIG.15shows a state in which both sides of the BP sheet330are exposed by removing outer portions of the 2D material layer320. The structure shown inFIG.15may be applied to electronic devices such as FETs as described later.

As described above, in the present example embodiment, the BP sheet330may be formed even at a relatively low pressure such as atmospheric pressure by using van der Waals pressure formed between the substrate110and the 2D material layer320.

The BP-2D material complexes 100 and 300 described above may be applied to various electronic devices such as FETs or photodetectors.

FIG.16shows an electronic device400(for example, an FET) according to an example embodiment.

Referring toFIG.16, the electronic device400includes: a BP-2D material complex; first and second electrodes441and442provided on both sides of the BP-2D material complex; and a third electrode450provided above an upper portion of the BP-2D material complex.

The BP-2D material complex is provided on an upper surface of a substrate410. Here, a substrate including an insulating material may be used as the substrate410. The BP-2D material complex may be manufactured by the method described with reference toFIGS.4to9.

For example, the BP-2D material complex includes a BP sheet430, a first 2D material layer422provided on an upper surface of the BP sheet430, and a second 2D material layer421provided on a lower surface of the BP sheet430. Here, both sides of the BP sheet430are not covered by the first and second 2D material layers422and421and are thus open.

Because BP sheets have been described above, a detailed description of the BP sheet430will be omitted. The BP sheet430may have a single-layer structure or a multilayer structure. The BP sheet430may include, for example, one to fifty layers. In this case, the BP sheet430may have a thickness of about 10 nm or less.

The first and second 2D material layers422and421are provided on the upper and lower surfaces of the BP sheet430, respectively. The first and second 2D material layers422and421may include a 2D material that is different from the material of the BP sheet430. For example, the first and second 2D material layers422and421may include an insulating 2D material such as h-BN.

Each of the first and second 2D material layers422and421may have a single-layer structure or a multilayer structure. For example, each of the first and second 2D material layers422and421may have a thickness of about 10 nm or less.

Each of the first and second 2D material layers422and421is coupled to the BP sheet430by van der Waals force. Here, the distance between the BP sheet430and each of the first and second 2D material layers422and421may be, for example, about 0.8 nm or less.

The first and second electrodes441and442are provided on both sides of the BP-2D material complex. The first and second electrodes441and442may be provided to form edge contacts with the BP sheet430. For example, both lateral end portions of the BP sheet430are open by not being covered by the first and second 2D material layers422and421, and the open lateral end portions of the opened BP sheet430are electrically connected to the first and second electrodes441and442.

The first and second electrodes441and442may include a material having high conductivity. The first and second electrodes441and442may be a source electrode and a drain electrode, respectively. The BP sheet430provided between the first electrode441being a source electrode and the second electrode442being a drain electrode may serve as a channel.

The third electrode450may be provided on the first 2D material layer422between the first and second electrodes441and442. The third electrode450may be a gate electrode. In addition, an insulating layer455may be provided between the first 2D material layer422and the third electrode450. The insulating layer455may be a gate insulating layer.

FIG.17is a view illustrating an electronic device500according to another example embodiment. The electronic device500illustrated inFIG.17is the same as the electronic device400illustrated inFIG.16except that a 2D material layer is not provided on a lower surface of a BP sheet430.

Referring toFIG.17, a BP-2D material complex includes the BP sheet430and a 2D material layer520provided on an upper surface of the BP sheet430. The 2D material layer520may include an insulating 2D material such as h-BN. The BP-2D material complex may be manufactured, for example, by the method described with reference toFIGS.11to15.

FIG.18is a view illustrating an electronic device600according to another example embodiment.

Referring toFIG.18, the electronic device600includes: a BP-2D material complex; first and second electrodes641and642which are respectively provided on both sides of the BP-2D material complex; and a third electrode650which is provided above an upper portion of the BP-2D material complex.

The BP-2D material complex includes a BP sheet630, a first 2D material layer622provided on an upper surface of the BP sheet630, and a second 2D material layer621provided on a lower surface of the BP sheet630. The first and second 2D material layers622and621may include a 2D material that is different from the material of the BP sheet630. For example, the first and second 2D material layers622and621may include an insulating 2D material such as h-BN.

The first and second electrodes641and642are provided on both sides of the BP-2D material complex. The first and second electrodes641and642may be provided to form planar contacts with the BP-2D material complex. For example, the first and second electrodes641and642may respectively be in contact with upper surfaces of both sides of the first 2D material layer622. The first and second electrodes641and642may be a source electrode and a drain electrode, respectively. The BP sheet630may serve as a channel. In this case, electric charges may move between the first electrode641and the BP sheet630and between the second electrode642and the BP sheet630by the tunneling effect.

The third electrode650may be provided above an upper portion of the first 2D material layer622between the first and second electrodes641and642, and an insulating layer655may be provided between the first 2D material layer622and the third electrode650. The third electrode650may be a gate electrode, and the insulating layer655may be a gate insulating layer.

FIG.19is a view illustrating an electronic device700according to another example embodiment. The electronic device700illustrated inFIG.19is the same as the electronic device600illustrated inFIG.18except that a 2D material layer is not provided on a lower surface of a BP sheet630.

Referring toFIG.19, a BP-2D material complex includes the BP sheet630and a 2D material layer720provided on an upper surface of the BP sheet630. The 2D material layer720may include an insulating 2D material such as h-BN.

FIG.20is a view illustrating an electronic device800according to another example embodiment.

Referring toFIG.20, the electronic device800includes: a BP-2D material complex; first and second electrodes841and842which are respectively provided on both sides of the BP-2D material complex; and a third electrode850which is provided above an upper portion of the BP-2D complex.

The BP-2D material complex includes a BP sheet830, a first 2D material layer822provided on an upper surface of the BP sheet830, and a second 2D material layer821provided on a lower surface of the BP sheet830. The first 2D material layer822provided on the upper surface of the BP sheet830may include fluorinated graphene822band graphene822aprovided on both sides of the fluorinated graphene822b. Here, the fluorinated graphene822bis an insulating material and may be formed by fluorinating the graphene882ausing, for example, XeF2or SF6. The second 2D material layer821provided on the lower surface of the BP sheet830may include an insulating 2D material such as h-BN.

The first and second electrodes841and842are provided on both sides of the BP-2D material complex. The first and second electrodes841and842may be provided to form planar contacts with the BP-2D material complex. For example, the first and second electrodes841and842may be provided on the first 2D material layer822and may be in contact with the graphene822awhich is provided on both sides of the fluorinated graphene822b.

The first and second electrodes841and842may be a source electrode and a drain electrode, respectively. The BP sheet830may serve as a channel. The third electrode850may be provided above an upper portion of the first 2D material layer822between the first and second electrodes841and842, and an insulating layer855may be provided between the first 2D material layer822and the third electrode850. The third electrode850may be a gate electrode, and the insulating layer855may be a gate insulating layer.

FIG.21is a view illustrating an electronic device900according to another example embodiment. The electronic device900illustrated inFIG.21is the same as the electronic device800illustrated inFIG.20except that a 2D material layer is not provided on a lower surface of a BP sheet830.

Referring toFIG.21, a BP-2D material complex includes the BP sheet830and a 2D material layer920provided on an upper surface of the BP sheet830. Here, the 2D material layer920may include fluorinated graphene920band graphene920aprovided on both sides of the fluorinated graphene920b.

As described above, according to the one or more of the above embodiments, a BP sheet and a BP-2D material complex may easily be formed even at a relatively low pressure such as atmospheric pressure by using a great van der Waals pressure formed between first and second 2D material layers or between a substrate and a 2D material layer.

In addition, because the BP sheet is encapsulated by the first and second 2D material layers, the BP sheet may be protected from external environments such as an oxidizing environment. Because the BP sheet has semiconductor characteristics, high charge mobility, and a high on/off current ratio, the BP-2D material complex including the BP sheet may be applied to various electronic devices such as FETs or photo detectors. While embodiments have been described above, the embodiments are examples, and those of ordinary skill in the art could easily make various changes or modifications in the embodiments.

It should be understood that embodiments described herein should be considered in a descriptive sense only and not for purposes of limitation. Descriptions of features or aspects within each embodiment should typically be considered as available for other similar features or aspects in other embodiments. While one or more embodiments have been described with reference to the figures, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope as defined by the following claims.