Query: Phosphorus-Doped Silicon  Nanocrystals Exhibiting Mid-Infrared Localized Surface Plasmon Resonance

Candidate papers:

abstract: Localized surface plasmon resonances (LSPRs) enable tailoring of the optical response of nanomaterials through their free carrier concentration, morphology, and dielectric environment. Recent efforts to expand the spectral range of usable LSPR frequencies into the infrared successfully demonstrated LSPRs in doped semiconductor nanocrystals. Despite silicon's importance for electronic and photonic applications, no LSPRs have been reported for doped silicon nanocrystals. Here we demonstrate doped silicon nanocrystals synthesized via a nonthermal plasma technique that exhibits tunable LSPRs in the energy range of 0.07 0.3 eV or mid infrared wavenumbers of 600 2500 cm( 1)
author_names: David J Rowe

Jong Seok Jeong

K Andre Mkhoyan

Uwe R Kortshagen
title: Phosphorus doped silicon nanocrystals exhibiting mid infrared localized surface plasmon resonance.
venue: Nano letters
year: 2013

abstract: Extended abstract of a paper presented at Microscopy and Microanalysis 2013 in Indianapolis, Indiana, USA, August 4 August 8, 2013.
author_names: Jong Seok Jeong

David J Rowe

Uwe R Kortshagen

K Andre Mkhoyan
title: Analytical STEM Study of P Doped Silicon Nanocrystals Exhibiting Mid Infrared Localized Surface Plasmon Resonance
venue: Microscopy and Microanalysis
year: 2013

abstract: Localized surface plasmon resonance (LSPR) of doped Si nanocrystals (NCs) is critical to the development of Si based plasmonics. We now experimentally show that LSPR can be obtained from both B and P doped Si NCs in the mid infrared region. Both experiments and calculations demonstrate that the Drude model can be used to describe the LSPR of Si NCs if the dielectric screening and carrier effective mass of Si NCs are considered. When the doping levels of B and P are similar, the LSPR energy of B doped Si NCs is higher than that of P doped Si NCs because B is more efficiently activated to produce free carriers than P in Si NCs. We find that the plasmonic coupling between Si NCs is effectively blocked by oxide at the NC surface. The LSPR quality factors of B and P doped Si NCs approach those of traditional noble metal NCs. We demonstrate that LSPR is an effective means to gain physical insights on the electronic properties of doped Si NCs. The current work on the model semiconductor NCs, i.e. Si NCs has important implication for the physical understanding and practical use of semiconductor NC plasmonics.
author_names: Shu Hong Zhou

Xiaodong Pi

Zhenyi Ni

Yi Ding

Yingying Jiang

Chuanhong Jin

Christophe Delerue

Deren Yang

Tomohiro Nozaki
title: Comparative study on the localized surface plasmon resonance of boron and phosphorus doped silicon nanocrystals.
venue: ACS nano
year: 2015

abstract: Colloidal nanocrystals of anatase TiO2 exhibit localized surface plasmon resonance (LSPR) in the mid infrared upon carrier accumulation through synthetic doping or electrochemical reduction. However, the energy and intensity of LSPR in anatase TiO2 nanocrystals is anomalously low compared to those of other transparent conductive oxides with similar bulk conductivity. Here, the electronic origin of LSPR energy and intensity in TiO2 nanocrystals is quantified by measuring infrared transmittance of dilute dispersions of doped nanocrystals and ex situ charged thin films. Optical modeling of infrared spectra reveals that TiO2 nanocrystals can accommodate carrier concentrations exceeding 1.5 x 1021 cm 3 upon charging, but the large effective mass along the anatase c axis is found to diminish the infrared absorption of TiO2 nanocrystals. The respective effects of crystalline anisotropy, synthetic doping, and electrochromic charging on LSPR in TiO2 nanocrystals are investigated, revealing promising new avenues to.
author_names: Clayton J Dahlman

Ankit Agrawal

Corey M Staller

Jacob Adair

Delia J Milliron
title: Anisotropic Origins of Localized Surface Plasmon Resonance in n Type Anatase TiO2 Nanocrystals
year: 2019

abstract: A central theme of nanocrystal (NC) research involves the synthesis of dimension controlled NCs and studies of size dependent scaling laws governing their optical, electrical, magnetic, and thermodynamic properties. Here we describe the synthesis of monodisperse CdO NCs that exhibit high quality factor (up to 5.5) mid infrared (MIR) localized surface plasmon resonances (LSPR) and elucidate the inverse scaling relationship between carrier concentration and NC size. The LSPR wavelength is readily tunable between 2.4 and ~6.0 mm by controlling the size of CdO NCs. Structural and spectroscopic characterization provide strong evidence that free electrons primarily originate from self doping due to NC surface induced nonstoichiometry. The ability to probe and to control NC stoichiometry and intrinsic defects will pave the way toward predictive synthesis of doped NCs with desirable LSPR characteristics.
author_names: Zeke Liu

Yaxu Zhong

Ibrahim Shafei

Soojin Jeong

Liguang Wang

Hoai Thuong Nguyen

Cheng Sun

Tao Li

Jianyun Chen

Liquan Chen

Yaroslav Losovyj

Xinfeng Gao

Wanli Ma

Xingchen Ye
title: Broadband Tunable Mid infrared Plasmon Resonances in Cadmium Oxide Nanocrystals Induced by Size dependent Nonstoichiometry.
venue: Nano letters
year: 2020

abstract: We observe and systematically tune an intense mid infrared absorption mode that results from phosphorus doping in silicon nanowires synthesized via the vapor liquid solid technique. The angle and shape dependence of this spectral feature, as determined via in situ transmission infrared spectroscopy, supports its assignment as a longitudinal localized surface plasmon resonance (LSPR) Modulation of resonant frequency (740 1620 cm( 1) is accomplished by varying nanowire length (135 1160 nm) The observed frequency shift is consistent with Mie Gans theory, which indicates electrically active dopant concentrations between 10(19) and 10(20) cm( 3) Our findings suggest new opportunities to confine light in this ubiquitous semiconductor and engineer the optical properties of nontraditional plasmonic materials.
author_names: Li-wei Chou

Naechul Shin

Saujan V Sivaram

Michael A Filler
title: Tunable mid infrared localized surface plasmon resonances in silicon nanowires.
venue: Journal of the American Chemical Society
year: 2012

abstract: Dynamic optical control of infrared (IR) transparency and refractive index is achieved using boron doped silicon nanocrystals excited with mid IR optical pulses. Unlike previous silicon based optical switches, large changes in transmittance are achieved without a fabricated structure by exploiting strong light coupling of the localized surface plasmon resonance (LSPR) produced from free holes of p type silicon nanocrystals. The choice of optical excitation wavelength allows for selectivity between hole heating and carrier generation through intraband or interband photoexcitation, respectively. Mid IR optical pumping heats the free holes of p Si nanocrystals to effective temperatures greater than 3500 K. Increases of the hole effective mass at high effective hole temperatures lead to a subpicosecond change of the dielectric function, resulting in a redshift of the LSPR, modulating mid IR transmission by as much as 27% and increasing the index of refraction by more than 0.1 in the mid IR. Low hole heat capacity dictates subpicosecond hole cooling, substantially faster than carrier recombination, and negligible heating of the Si lattice, permitting mid IR optical switching at terahertz repetition frequencies. Further, the energetic distribution of holes at high effective temperatures partially reverses the Burstein Moss effect, permitting the modulation of transmittance at telecommunications wavelengths. The results presented here show that doped silicon, particularly in micro or nanostructures, is a promising dynamic metamaterial for ultrafast IR photonics.
author_names: Benjamin T Diroll

Katelyn S Schramke

Peijun Guo

Uwe R Kortshagen

Richard D Schaller
title: Ultrafast Silicon Photonics with Visible to Mid Infrared Pumping of Silicon Nanocrystals.
venue: Nano letters
year: 2017

abstract: Degenerately doped semiconductor nanocrystals (NCs) exhibit strong light matter interactions due to localized surface plasmon resonance (LSPR) in the near to mid infrared region. Besides being readily tuned through dopant concentration introduced during synthesis, this LSPR can also be dynamically modulated by applying an external electrochemical potential. This characteristic makes these materials candidates for electrochromic window applications. Here, using prototypical doped indium oxide NCs as a model system, we find that the extent of electrochemical modulation of LSPR frequency is governed by the depletion width and the extent of inter NC LSPR coupling, which are indirectly controlled by the dopant density, size, and packing density of the NCs. The depletion layer is a near surface region with a sharply reduced free carrier population that occurs whenever the surface potential lies below the Fermi level. Changes in the depletion width under applied bias substantially control the spectral modulation of the LSPR of individual NCs and also modify the inter NC LSPR coupling, which additionally modulates the LSPR absorption on the NC film scale. Here, we show that both of these effects must be considered primary factors in determining the extent of LSPR frequency modulation and that the dominant factor depends on NC size. For a constant doping concentration, depletion effects govern LSPR modulation for smaller NCs, while LSPR coupling is prevalent in larger NCs. Consequently, as the size of the NCs is increased while keeping the doping concentration constant, we observe a reversal in the sign of the LSPR frequency modulation from positive to negative.
author_names: Bharat Tandon

Ankit Agrawal

Sung Yeon Heo

Delia J Milliron
title: Competition between Depletion Effects and Coupling in the Plasmon Modulation of Doped Metal Oxide Nanocrystals.
venue: Nano letters
year: 2019

abstract: Metal oxides, when electronically doped with oxygen vacancies, aliovalent dopants, or interstitial dopants, can exhibit metallic behavior due to the stabilization of a substantial charge carrier concentration within the material. As a result, localized surface plasmon resonances (LSPRs) occur in nanocrystals of conducting metal oxides. Through deliberate choice of both the host material and the defect, these resonances can be tuned across the entirety of the near and mid infrared regions of the electromagnetic spectrum. Optical modeling has revealed that the defects present have profound impacts on charge carrier mobility and electronic structure, and in some cases, choosing one dopant over another is an important trade off for optimizing plasmonic performance. These materials are distinct from classical metals in that one can tune their LSPR in energy and intensity through their elemental composition independently of any particular size or nanocrystal morphology. In addition, the LSPR in these materials.
author_names: Ankit Agrawal

Robert W Johns

Delia J Milliron
title: Control of Localized Surface Plasmon Resonances in Metal Oxide Nanocrystals
year: 2017

abstract: Degenerately doped silicon nanocrystals are appealing plasmonic materials due to silicon's low cost and low toxicity. While surface plasmonic resonances of boron doped and phosphorus doped silicon nanocrystals were recently observed, there currently is poor understanding of the effect of surface conditions on their plasmonic behavior. Here, we demonstrate that phosphorus doped silicon nanocrystals exhibit a plasmon resonance immediately after their synthesis but may lose their plasmonic response with oxidation. In contrast, boron doped nanocrystals initially do not exhibit plasmonic response but become plasmonically active through postsynthesis oxidation or annealing. We interpret these results in terms of substitutional doping being the dominant doping mechanism for phosphorus doped silicon nanocrystals, with oxidation induced defects trapping free electrons. The behavior of boron doped silicon nanocrystals is more consistent with a strong contribution of surface doping. Importantly, boron doped silicon nanocrystals exhibit air stable plasmonic behavior over periods of more than a year.
author_names: Nicolaas J Kramer

Katelyn S Schramke

Uwe R Kortshagen
title: Plasmonic Properties of Silicon Nanocrystals Doped with Boron and Phosphorus.
venue: Nano letters
year: 2015