Cookies ussage consent
Our site saves small pieces of text information (cookies) on your device in order to deliver better content and for statistical purposes. You can disable the usage of cookies by changing the settings of your browser. By browsing our site without changing the browser settings you grant us permission to store that information on your device.I agree, do not show this message again.
- Department of Applied Physics, Graduate School of Engineering, Hokkaido University, Sapporo Kita ku, 060 8628, Japan
After briefly reviewing e lectr onic properties governed by gap states in amorphous and glassy Se we consider the responsible structur es through empirical and ab initio molecular orbital calculations . So far m any fundamental and application oriented studies on Se have been performed , respectively, for melt quenched glasses and evaporated amorphous films, while the atomic structur es producing gap states still remain vague. The calculation for Se clusters such as H n Se H demonstrate s that v ariations of d ihedral angle s and i nter cluster separation s bring substantial fluctuation s in the HOMO energy , which ma y cause hole traps in solid Se . The LUMO energy varies with n which suggests that long n ≥ 5) chain segments behave as electron traps. Small rings and d angling bonds create several gap states , which may work as trap s and absorption centers F or extrinsic defect s, oxygen effects have been emphasized . T he calculation demonstrate s that O atom s behave as potent isoelectronic impurities, being negatively charged , making nearest neighbor Se atoms positive Such an ionic pair can produce a deep LUMO level , which possibly work s as an a cceptor . Compens ation effects of As (and Si) into O contaminated Se are ascribed to the production of stronger As ( O bonds, which are electrically inactive due to wider HOMO LUMO gaps ..
: Amorphous, Selenium, Oxygen, Gap state, Defect, Impurity.
Submitted at: Sept. 17, 2015
Accepted at: Oct. 28, 2015
K. TANAKA, Gap states in non crystalline selenium: roles of d efect ive structure s and impurities, Journal of Optoelectronics and Advanced Materials Vol. 17, Iss. 11-12, pp. 1716-1727 (2015)
- Download Fulltext
- Downloads: 61 (from 45 distinct Internet Addresses ).