Scanning tunneling spectra for the etched surface of p type HgCdTe
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

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 bulk 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.