液相外延p型碲镉汞表面区与腐蚀凹坑的不同扫描隧道谱特征  

Scanning tunneling spectra for the etched surface of p-type HgCdTe

作　　者：王庆余[1] 任秀荣[1] 李茂森[1] 徐德政[1] 查访星[1,2] 

机构地区：[1]上海大学理学院物理系和微结构实验室,上海200444 [2]中国科学院上海技术物理研究所红外物理国家重点实验室,上海200083

出　　处：《红外与毫米波学报》2012年第3期222-225,共4页Journal of Infrared and Millimeter Waves

基　　金：国家自然科学基金973项目(2010CB630704)~~

摘　　要：利用超高真空扫描隧道显微镜对经过溴甲醇溶液腐蚀处理的液相外延碲镉汞材料进行了表征.发现经过腐蚀处理(3%浓度,2.5 min)的样品表面出现高密度的凹坑结构,凹坑深度约几十纳米,横向尺度在几十到几百纳米之间.扫描隧道谱测量表明,腐蚀样品表面平坦区呈现较大表观带隙,需考虑针尖诱导的能带弯曲效应,而凹坑区在零偏压区的扫描隧道谱线则近似为线性变化,说明该区域包含较高的带隙态并直接参与隧穿,从而掩盖了带隙信息.Ultra-high vacuum scanning tunneling microscopy （STM） and spectroscopy （ STS ） were used to characterize Hg1-xCdxTe grown by liquid-phase epitaxy （LPE） method. The sample was etched with 3% Bromine-methanol in 2.5 minutes. The STM images display submicrometer-sized pit structures with depths ranging from a few tens to a few hundreds nanometers. The scanning tunneling spectra show a larger apparent gap than the energy band gap of the btilk material due to the tip-induced band bending effect. In contrast, the scanning tunneling spectra of the pits show a finite slope through zero volt, implying the contribution of high density of band gap states which blur out the band gap information.

关 键 词：碲镉汞 扫描隧道显微镜 隧道谱 

分 类 号：TN215[电子电信—物理电子学]