Search query: Growth and magnetic properties of Mn-doped germanium near the kinetic solubility limit

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abstract: Growth of high quality dilute magnetic semiconductor (DMS) material is often compromised by the low solubility of magnetic dopants, leading to formation of precipitates. Here, we explore the feasibility of growing precipitate free Mn doped Ge at doping levels near the kinetic solubility limit. Ge:Mn DMS films were grown at low temperature so as to minimize precipitate formation. Meanwhile, epitaxial quality was maintained by employing a very low growth rate. The magnetic properties of these lightly doped films exhibit both interesting contrasts and similarities with those of heavily doped DMS reported in the literature, indicating that the substitutional Mn contents are very similar. Films grown at 95 degree C are free of intermetallic precipitates, offering useful opportunities for studying the fundamentals of carrier mediated exchange and metal insulator transitions without complications arising from precipitate formation.
author_names: Mustafa M Ozer

James R Thompson

Hanno H Weitering
title: Growth and magnetic properties of Mn doped germanium near the kinetic solubility limit
year: 2012

abstract: Zinc oxide is a unique material that exhibits semiconducting and piezoelectric dual properties. Using a solid vapour phase thermal sublimation technique, nanocombs, nanorings, nanohelixes/nanosprings, nanobelts, nanowires and nanocages of ZnO have been synthesized under specific growth conditions. These unique nanostructures unambiguously demonstrate that ZnO probably has the richest family of nanostructures among all materials, both in structures and in properties. The nanostructures could have novel applications in optoelectronics, sensors, transducers and biomedical sciences. This article reviews the various nanostructures of ZnO grown by the solid vapour phase technique and their corresponding growth mechanisms. The application of ZnO nanobelts as nanosensors, nanocantilevers, field effect transistors and nanoresonators is demonstrated.
author_names: Zhong Lin Wang
title: Zinc oxide nanostructures: growth, properties and applications
year: 2004

abstract: Mn+ ions were implanted into n type Ge(111) single crystal at room temperature at an energy of 100 keV with a dose of 3 x 1016 cm 2. Subsequent annealing was performed on the samples at 400 degC and 600 degC in a flowing nitrogen atmosphere. The magnetic properties of the samples have been investigated by alternating gradient magnetometer at room temperature. The compositional properties of the annealed samples were studied by Auger electron spectroscopy and the structural properties were analyzed by X ray diffraction measurements. Magnetization measurements reveal room temperature ferromagnetism for the annealed samples. The magnetic analysis supported by compositional and structural properties indicates that forming the diluted magnetic semiconductor (DMS) MnxGe1 x after annealing may account for the ferromagnetic behavior in the annealed samples.
author_names: Liu Li-feng

Chen Nuo-fu

Chen Chenlong

Li Yanli

Yin Zhigang

Yang Fei
title: Magnetic Properties of Mn Implanted n Type Ge
year: 2004

abstract: Ferromagnetism in manganese compound semiconductors not only opens prospects for tailoring magnetic and spin related phenomena in semiconductors with a precision specific to III V compounds but also addresses a question about the origin of the magnetic interactions that lead to a Curie temperature (T(C) as high as 110 K for a manganese concentration of just 5% Zener's model of ferromagnetism, originally proposed for transition metals in 1950, can explain T(C) of Ga(1 (x)Mn(x)As and that of its II VI counterpart Zn(1 (x)Mn(x)Te and is used to predict materials with T(C) exceeding room temperature, an important step toward semiconductor electronics that use both charge and spin.
title: Zener model description of ferromagnetism in zinc blende magnetic semiconductors
venue: Science
year: 2000

abstract: We report the growth of free standing one dimensional Ge/Mn germanide nanowire heterostructures by chemical vapor deposition and provide a detailed description of the growth mechanism. Self assembled manganese germanide particles seed the growth of Ge nanowires (GeNWs) and simultaneously elongate along a parallel axis, resulting in syntaxial growth of the two phases. The GeNW growth is limited by GeH 4 decomposition, whereas the germanide growth is limited by reaction of Mn at the growth interface. This syntaxial growth mechanism provides a novel route to axial metal/semiconductor nanowire heterostructures.
author_names: Jessica L Lensch-Falk

Eric R Hemesath

Lincoln J Lauhon
title: Syntaxial growth of Ge/Mn germanide nanowire heterostructures.
venue: Nano letters
year: 2008

abstract: A new GaAs based diluted magnetic semiconductor, (Ga,Mn)As, was prepared by molecular beam epitaxy. The lattice constant of (Ga,Mn)As films was determined by x ray diffraction and shown to increase with the increase of Mn composition, x. Well aligned in plane ferromagnetic order was observed by magnetization measurements. Magnetotransport measurements revealed the occurrence of anomalous Hall effect in the (Ga,Mn)As layer.
author_names: Hideo Ohno

Aidong Shen

Fumihiro Matsukura

Akira Oiwa

Akira Endo

S Katsumoto

Yasuhiro Iye
title: (Ga,Mn)As: A new diluted magnetic semiconductor based on GaAs
year: 1996

abstract: We measured the elastic properties and intrinsic breaking strength of free standing monolayer graphene membranes by nanoindentation in an atomic force microscope. The force displacement behavior is interpreted within a framework of nonlinear elastic stress strain response, and yields second and third order elastic stiffnesses of 340 newtons per meter (N m 1) and 690 Nm 1, respectively. The breaking strength is 42 N m 1 and represents the intrinsic strength of a defect free sheet. These quantities correspond to a Young's modulus of E 1.0 terapascals, third order elastic stiffness of D 2.0 terapascals, and intrinsic strength of sint 130 gigapascals for bulk graphite. These experiments establish graphene as the strongest material ever measured, and show that atomically perfect nanoscale materials can be mechanically tested to deformations well beyond the linear regime.
author_names: Changgu Lee

Xiaoding Wei

Jeffrey W Kysar

James C Hone
title: Measurement of the Elastic Properties and Intrinsic Strength of Monolayer Graphene
venue: Science
year: 2008

abstract: 3 To my family and friends who have made this dissertation possible 4 ACKNOWLEDGMENTS I would like to acknowledge my family for stressing the importance of an education and always being there for me. I would also like to thank my close friends for offering support and making my graduate experience an enjoyable one. This dissertation would not have been possible without these people. I also want to thank Ludovic Godet for hiring me as an intern at Varian Semiconductor Equipment Associates (VSEA) and giving me freedom to pursue my own ideas in research and development. Ludo always took the time to answer my questions and gave me extraordinary exposure within the company. I would also like to acknowledge Alex Kontos at VSEA and Rob Elliman at Australian National University for doing the implants for this research. I would also like to thank my advisor Kevin Jones and my committee members. I originally came to UF as a master's student and when I asked Dr. Jones whether he knew of any openings for part time research, he immediately offered me a position to join his group. I am also grateful for his trust in me and willingness to allow me to pursue research interests, even if they were slightly off topic. Last, but not least I would like to acknowledge the past and present SWAMP group members: has provided numerous thoughtful discussions and created an environment that constantly pushed one another to learn new things.
author_names: Brendan L Darby
title: Amorphization and solid phase epitaxial growth of germanium
year: 2012

abstract: Problems associated with large scale pattern growth of graphene constitute one of the main obstacles to using this material in device applications. Recently, macroscopic scale graphene films were prepared by two dimensional assembly of graphene sheets chemically derived from graphite crystals and graphene oxides. However, the sheet resistance of these films was found to be much larger than theoretically expected values. Here we report the direct synthesis of large scale graphene films using chemical vapour deposition on thin nickel layers, and present two different methods of patterning the films and transferring them to arbitrary substrates. The transferred graphene films show very low sheet resistance of ~280 O per square, with ~80 per cent optical transparency. At low temperatures, the monolayers transferred to silicon dioxide substrates show electron mobility greater than 3,700 cm2 V 1 s 1 and exhibit the half integer quantum Hall effect, implying that the quality of graphene grown by chemical vapour deposition is as high as mechanically cleaved graphene. Employing the outstanding mechanical properties of graphene, we also demonstrate the macroscopic use of these highly conducting and transparent electrodes in flexible, stretchable, foldable electronics.
author_names: Keun Soo Kim

Yuer Zhao

Houk Jang

Sang Yoon Lee

Jong Min Kim

Kwang Suk Kim

Jong-Hyun Ahn

Philip Kim

Jaeyoung Choi

Byung Hee Hong
title: Large scale pattern growth of graphene films for stretchable transparent electrodes
venue: Nature
year: 2009

abstract: The use of bis trimethylsilylamide transition metal complexes soluble in organic solvents offers new perspectives for the synthesis of metal chalcogenide cluster molecules, especially for multicomponent clusters. This is illustrated by the synthesis of the mixed cadmium manganese chalcogenide clusters [Cd(4)Mn(6)Se(4)(SePh)(12)(P(n)Pr(3)(4) and [Cd(4)Mn(4)S(SePh)(14)(P(n)Pr(3)(2) as reported here. These cluster molecules display interesting properties, such as a photoluminescence in the red to near infrared spectral region, which is particularly bright at temperatures below approximately 100 K, and an antiferromagnetic coupling between the manganese(II) ions. Electrospray Fourier transform ion cyclotron resonance mass spectra from the chemically charged clusters in solution show several ionic cluster species which indicate a fast Cd/Mn exchange in solution. Furthermore, single crystal X ray analysis and magnetic measurements supported by density functional theory calculations suggest a cocrystallization of structural isomers of the ideal cluster composition [Cd(4)Mn(4)S(SePh)(14)(P(n)Pr(3)(2) as well as of species with the general formula [Cd(4+x)Mn(4 x)S(SePh)(14)(P(n)Pr(3)(2) (x 0 Mn enrichment; x 0 Cd enrichment) without a significant decrease in the stability. Thermal cleavage of [Cd(4)Mn(6)Se(4)(SePh)(12)(P(n)Pr(3)(4) results, in agreement with the CdSe/MnSe phase diagram, in the formation of a mixture of a hexagonal phase Cd(1 x)Mn(x)Se (x approximately 0.5) and a cubic phase Mn(1 x)Cd(x)Se (x 0.05)
author_names: Andreas Eichhofer

Oliver Hampe

Sergei F Lebedkin

Florian Weigend
title: Bistrimethylsilylamide transition metal complexes as starting reagents in the synthesis of ternary Cd Mn Se cluster complexes.
venue: Inorganic chemistry
year: 2010