Nonorganic semiconductor - Conductive polymer intercalate nanohybrids: Fabrication, properties, application

Impedance spectroscopy studies performed for intercalated multilayer structures of the type of a layered inorganic semiconductor (InSe)/conducting polymer (PEDOT:PSS) revealed low-frequency inductive response and the growth of dielectric permeability in megahertz region together with the decrease of dielectric loss angle down to one as a consequence of the conducting polymer intercalation into semiconducting layers. A model describing the unusual current-voltage characteristic is proposed.     

化学气相沉积法制备InSe纳米片及其近红外光探测性能

采用化学气相沉积法在云母衬底上制备了二维InSe纳米片, 研究了生长温度对二维InSe纳米片晶相、 形貌、 尺寸及厚度的影响. 构筑了基于二维InSe纳米片的光探测器并研究了其光探测性能, 结果表明, 在808 nm的近红外光辐照下, 其光响应度为1.5 A/W, 外量子效率为230%, 可探测度为3.1×10 ⁸ Jones(1 Jones=1 cm·Hz ^1/2·W ^-1), 上升和衰减时间分别为0.5 和0.8 s.     

Fabrication and lithium electrochemistry of InSe thin film

InSe thin film has been successfully fabricated by pulsed-laser deposition method. Electrochemical behavior of Li/InSe cell has been investigated by Galvanostatic cycling and cyclic voltammetry measurements for the first time. The reversible capacity of InSe electrode of 410 mAh/g with the volumetric capacity of about 3302 mAh/cm³ was achieved at a current density of 0.05 mA/cm². By using XRD and XPS measurements, both alloying/de-alloying processes and selenidation/reduction processes were revealed during the electrochemical cycling of InSe thin film electrode. InSe was found to be a novel candidate of anode materials for rechargeable lithium batteries.     

二维InSe/SnSe2范德华异质结的电子结构和光学特性研究

本文构建了三种不同堆叠形式下的二维InSe/SnSe₂范德华异质结模型,利用基于密度泛函理论的第一性原理方法综合考察了二维InSe/SnSe₂三种不同堆叠情况下的几何构型及稳定性,在此基础上选取具有最稳定性能的构型.该异质结呈现出Ⅱ型能带对齐特征,带隙值为1.118 eV,可以实现电子-空穴的有效分离.另外,相比与单层二维InSe/SnSe₂范德华异质结的光吸收能力达到明显提升,在紫外光范围内吸收系数达到10~6 cm^-1.研究结果将为相关物理实验及机理研究提供理论基础,对二维InSe/SnSe₂范德华异质结在光电器件中的应用具有重要的物理意义.     

Effect of substrate temperature on the properties of vacuum evaporated indium selenide thin films

Thin films of InSe were obtained by thermal evaporation techniques on glass substrates maintained at various temperatures (T_sb = 30°, 400°C). X‐ray diffraction analysis showed the occurrence of amorphous to polycrystalline transformation in the films deposited at higher substrate temperature (400°C). The polycrystalline films were found to have a hexagonal lattice. Compositions of these films have been characterized by EDAX and the surface analysis by scanning electron microscopy. Optical properties of the films, investigated by using spectrophotometer transmittance spectra in the wavelength range (300 – 1100 nm), were explained in terms of substrate temperatures. Films formed at room temperature showed an optical band gap (E_g^opt) 1.56 eV; where as the films formed at 400°C were found to have a E_g^opt of 1.92 eV. The increase in the value of E_g^opt with T_sb treatment is interpreted in terms of the density of states model as proposed by Mott and Davis. The analysis of current ‐Voltage characteristics, based on space charge limited currents (SCLC) measurements, confirms the exponential decrease of density of states from the conduction band edge towards the Fermi level for both the amorphous and polycrystalline films. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Preparation and characterization of electrodeposited indium selenide thin films

Indium Selenide (InSe) thin films were deposited from a mixture of Indium chloride and selenium dioxide in aqueous solution by electrodeposition technique on Indium Tin oxide coated glass substrates. The effects of the parameters during deposition such as current density, deposition potential versus saturated calomel electrode, pH value and concentration of source material were studied. X‐ray diffraction studies were carried out on the films to analyze the microstructure using an x‐ray diffractometer and were examined by RAMAN spectroscopy. The Raman peak position did not change much with chemical concentrations. Raman scattering due to the (LO) phonon was observed at 211 cm^–1. Optical absorption studies were performed with a double beam ultra violet‐visible –NIR spectrophotometer in the wavelength 300–1100 nm. The surface morphology of the layer was examined using a scanning electron micrograph. The composition of the films was studied using an Energy Dispersive Analysis by X‐Rays (EDAX).     

Characteristics of Al/p‐Cu0.5Ag0.5InSe2 Polycrystalline Thin Film Schottky Barrier Diodes

Al/p‐Cu_0.5Ag_0.5InSe₂ polycrystalline thin film Schottky barrier diodes have been prepared. The current‐voltage, capacitance‐voltage and photores ponse have been investigated. Various important physical parameters of the sediodes were derived from these measurements.     

AES, LEED and PYS investigation of Au deposits on InSe/Si(1 1 1) substrate

Auger Electron Spectroscopy (AES), Low Energy Electron Diffraction (LEED) and Photoelectron Yield Spectroscopy (PYS) measurements have been used to monitor the interaction of gold (Au) deposits on InSe/Si(1 1 1) substrate. Au has been sequentially deposed under ultra-high vacuum onto 40 Å-thick film of layered semiconductor InSe which is epitaxially grown by molecular beam epitaxy (MBE) on a Si(1 1 1)1 × 1-H substrate and kept at room temperature. Au coverage varies from 0.5 monolayer to 20 monolayers (ML) (in terms of InSe atomic surface plane: 1 ML = 7.2 1014 at/cm²) which is corresponding to 1.30 Å of Au-metal. The Au/InSe/Si(1 1 1) system was characterized as function of Au deposit, we noticed an interaction at room temperature starts as an apparent intercalation process until 5 ML. Beyond this dose Au islands begin to form on the sample surface without interaction with InSe substrate, thus the interface is far from to be a simple junction Au-InSe.     

InSe的高压电输运性质研究

高压下对InSe样品进行原位电阻率和霍尔效应测量. 电阻率测量结果显示, 样品在5–6 GPa区间呈现金属特性, 在12 GPa 的压力下发生由斜六方体层状结构到立方岩盐矿的结构相变, 且具有金属特性. 霍尔效应测量结果显示, 样品在6.6 GPa由p型半导体转变成n型半导体, 电阻率随着压力的升高而逐渐下降是由于载流子浓度升高引起的. 关键词： InSe 高压 电阻率 霍尔效应     

六角氮化硼(h-BN)对单层硒化铟(InSe)的调制效应及这一新结构的电子性质

采用基于密度泛函理论的第一性原理计算和分析了三种InSe/h-BN异质结的结构和电子性质.研究发现InSe/h-BN异质结具有间接带隙特点,并且价带顶和导带底的贡献均来自于InSe,差分电荷密度表明体系中没有明显的电荷交换.通过体系能带结构,我们发现h-BN层对单层InSe有着明显的调控效应.对比纯粹应变调控下单层的InSe的能带结构,发现h-BN对InSe能带结构的调控效应实际上是由InSe和h-BN之间的相互作用而诱导的晶格应变引起的.我们的研究结果表明,单层InSe沉积或生长在不同h-BN片上可以获得不同的晶格应变,实现对单层InSe能带结构的有效调控.