Hg0.72Cd0.28Te扫描隧道谱的模型解释OA北大核心CSTPCD
Model interpretation of Hg0.72Cd0.28Te scanning tunneling spectra
本工作利用截面扫描隧道显微镜(XSTM)研究了分子束外延生长的Hg0.72Cd0.28Te薄膜.扫描隧道谱(STS)测量表明,此碲镉汞材料的电流-电压(Ⅰ/Ⅴ)隧道谱呈现的零电流平台宽度(隧道谱表观带隙)比其实际材料带隙增大约130％,说明存在明显的针尖诱导能带弯曲(TIBB)效应.STS三维TIBB模型计算发现低成像偏压测量时获取的Ⅰ/Ⅴ隧道谱数据与理论计算结果有令人满意的一致性.然而较大成像偏压时所计算的Ⅰ/Ⅴ谱与实验谱线在较大正偏压区域存在一定偏离.这是目前的TIBB模型未考虑带带隧穿、缺陷辅助隧穿等碲镉汞本身的输运机制对隧道电流的影响造成的.
The cross-sectional scanning tunneling microscopy(XSTM)technique was used to study the cleaved surface of Hg0.72Cd0.28Te grown by molecular beam epitaxy.Measurements of scanning tunnel spectroscopy(STS)show that the width of zero current plateau(the apparent tunneling gap)of current-voltage(Ⅰ/Ⅴ)spectra is about 130％larger than the practical band gap of the material,implying the existence of obvious tip-induced band bending(TIBB)effect with the measurement.Based on the 3D TIBB model,the STS data can however be interpreted and the calculated Ⅰ/Ⅴ spectra are in good agreement with the measurement.Nevertheless,certain deviation appears for those Ⅰ/Ⅴ data which were ac-quired with a large imaging bias.This is because the current TIBB model does not take into account the transport mecha-nism of the material itself,for which the band-to-band tunneling,trap assisted tunneling etc.could be non-negligible factors for the tunneling.
肖正琼;戴昊光;刘欣扬;陈平平;查访星
上海大学 理学院 物理系,上海 200444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
物理学
扫描隧道显微镜扫描隧道谱HgCdTe针尖诱导能带弯曲
scanning tunneling microscopyscanning tunneling spectroscopyHgCdTetip-induced band bending
《红外与毫米波学报》 2024 (003)
302-306 / 5
国家自然科学基金面上项目(61874069) Supported by the General Program of National Natural Science Foundation of China(61874069)
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