在低覆盖度下Au/GaAs和Au/GaSb界面的开尔文探针电容电位差研究

Au/GaAs AND Au/GaSb INTERFACE STUDY AT LOW COVERAGE BY KELVIN CPD MEASUREMENT

介绍了在超高真空系统中利用开尔文探针电容电位差(CPD)方法,在低覆盖度下Au/GaAs和An/GaSb的界面研究工作.在劈裂后的GaSb和GaAs表面,经初始的亚单层Au淀积后,两者的CPD值均有很大的跳变.这是同这一事实相符合的:按照光发射谱测量,在Au淀积的最初阶段(约0.2ML的Au淀积层),费米能级就“钉住”在表面态.此外,Au/n-GaAs的界面实验表明:CPD值有显著的光效应,特别在小于1ML的Au淀积层的情形下.

The interface study on Au/GaSb and Au/GaAs at monolayer coverage in the UHV system by the Kelvin CPD method is presented. There are big jumps on well cleaved GaSb and GaAs surfaces after initial sub-monolayer gold deposition. It is consistent with the fact that the Fermi level is pinning at the surface states at the very beginning of Au deposition of about 0.2ML, according to the photoemission measurements. The experiments on Au/n-GaAs interface show that there are significant photo-effects on the CPD value, particularly in the case of less than 1 ML Au being deposited.