An Effective Approach to Improving Cadmium Telluride (111)A Surface by Molecular-Beam-Epitaxy Growth of Tellurium Monolayer

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• 作者：Jie Ren ; Li Fu ; Guang Bian ; Jie Su ; Hao Zhang ; Saavanth Velury ; Ryu Yukawa ; Longxiang Zhang ; Tao Wang ; Gangqiang Zha ; Rongrong Guo ; Tom Miller ; M. Zahid Hasan ; Tai-Chang Chiang
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2016
• 出版时间：January 13, 2016
• 年：2016
• 卷：8
• 期：1
• 页码：726-735
• 全文大小：699K
• ISSN：1944-8252

文摘

The surface cleansing treatment of non-natural cleavage planes of semiconductors is usually performed in vacuum using ion sputtering and subsequent annealing. In this Research Article, we report on the evolution of surface atomic structure caused by different ways of surface treatment as monitored by in situ core-level photoemission measurements of Cd-4d and Te-4d atomic levels and reflection high-energy electron diffraction (RHEED). Sputtering of surface increases the density of the dangling bonds by 50%. This feature and the less than ideal ordering can be detrimental to device applications. An effective approach is employed to improve the quality of this surface. One monolayer (ML) of Te grown by the method of molecular beam epitaxy (MBE) on the target surface with heating at 300 °C effectively improves the surface quality as evidenced by the improved sharpness of RHEED pattern and a reduced diffuse background in the spectra measured by high-resolution ultraviolet photoemission spectroscopy (HRUPS). Calculations have been performed for various atomic geometries by employing first-principles geometry optimization. In conjunction with an analysis of the core level component intensities in terms the layer-attenuation model, we propose a “vacancy site” model of the modified 1 ML-Te/CdTe(111)A (2 × 2) surface.