翻訳と辞書 Words near each other ・ Surface micromachining ・ Surface mining ・ Surface Mining Control and Reclamation Act of 1977 ・ Surface modification ・ Surface modification of biomaterials with proteins ・ Surface movement radar ・ Surface Ocean Lower Atmosphere Study ・ Surface of class VII ・ Surface of constant width ・ Surface of Eceon ・ Surface of general type ・ Surface of revolution ・ Surface Paradise ・ Surface phenomenon ・ Surface phonon ・ Surface photovoltage ・ Surface piercing ・ Surface plasmon ・ Surface plasmon polariton ・ Surface plasmon resonance ・ Surface plasmon resonance microscopy ・ Surface plate ・ Surface power density ・ Surface pressure ・ Surface printing ・ Surface Pro ・ Surface Pro 2 ・ Surface Pro 3 ・ Surface Pro 4 ・ Surface probability Dictionary Lists mini英和辞書 mini和英辞書 Webster 1913 Latin-English FOLDOC Wikipedia English ウィキペディア

翻訳と辞書　辞書検索 [ 開発暫定版 ] スポンサード リンク Surface photovoltage ： ウィキペディア英語版 Surface photovoltage Surface photovoltage (SPV) measurements are a widely used method to determine the minority carrier diffusion length of semiconductors. Since the transport of minority carriers determines the behavior of the p-n junctions that are ubiquitous in semiconductor devices, surface photovoltage data can be very helpful in understanding their performance. As a contactless method, SPV is a popular technique for characterizing poorly understood compound semiconductors where the fabrication of ohmic contacts or special device structures may be difficult. == Theory== As the name suggests, SPV measurements involve monitoring the potential of a semiconductor surface while generating electron-hole pairs with a light source. The surfaces of semiconductors are often depletion regions (or space charge regions) where a built-in electric field due to defects has swept out mobile charge carriers. A reduced carrier density means that the electronic energy band of the majority carriers is bent away from the Fermi level. This band-bending gives rise to a surface potential. When a light source creates electron-hole pairs deep within the semiconductor, they must diffuse through the bulk before reaching the surface depletion region. The photogenerated minority carriers have a shorter diffusion length than the much more numerous majority carriers, with which they can radiatively recombine. The change in surface potential upon illumination is therefore a measure of the ability of minority carriers to reach the surface, namely the minority carrier diffusion length. As always in diffusive processes, the diffusion length $L$ is approximately related to the lifetime $\backslash tau\_\backslash mathrm$ by the expression $L\; =\; \backslash sqrt\; =\; \backslash sqrt$ where $\backslash tau\_\backslash mathrm$ is the effective carrier lifetime, $\backslash tau\_\backslash mathrm$ is the bulk carrier lifetime, $s$ is the surface recombination velocity and $d$ is the film or wafer thickness. Even for well characterized materials, uncertainty about the value of the surface recombination velocity reduces the accuracy with which the diffusion length can be determined for thinner films. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Surface photovoltage」の詳細全文を読む スポンサード リンク 翻訳と辞書 : 翻訳のためのインターネットリソース Copyright(C) kotoba.ne.jp 1997-2016. All Rights Reserved.