Origins of Hole Doping and Relevant Optoelectronic Properties of Wide Gap p-Type Semiconductor, LaCuOSe

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• 作者：Hidenori Hiramatsu ; Toshio Kamiya ; Tetsuya Tohei ; Eiji Ikenaga ; Teruyasu Mizoguchi ; Yuichi Ikuhara ; Keisuke Kobayashi ; Hideo Hosono
• 刊名：Journal of the American Chemical Society
• 出版年：2010
• 出版时间：October 27, 2010
• 年：2010
• 卷：132
• 期：42
• 页码：15060-15067
• 全文大小：485K
• 年卷期：v.132,no.42(October 27, 2010)
• ISSN：1520-5126

文摘

LaCuOSe is a wide band gap (2.8 eV) semiconductor with unique optoelectronic properties, including room-temperature stable excitons, high hole mobility 8 cm²/(Vs), and the capability of high-density hole doping (up to 1.7 × 10²¹ cm⁻³ using Mg). Moreover, its carrier transport and doping behaviors exhibit nonconventional results, e.g., the hole concentration increases with decreasing temperature and the high hole doping does not correlate with other properties such as optical absorption. Herein, secondary ion mass spectroscopy and photoemission spectroscopy reveal that aliovalent ion substitution of Mg at the La site is not the main source of hole doping and the Fermi level does not shift even in heavily doped LaCuOSe:Mg. As the hole concentration increases, the subgap optical absorption becomes more intense, but the increase in intensity does not correlate quantitatively. Transmission electron microscopy indicates that planar defects composed of Cu and Se deficiencies are easily created in LaCuOSe. These observations can be explained via the existence of a degenerate low-mobility layer and formation of complex Cu and Se vacancy defects with the assistance of generalized gradient approximation band calculations.