Low-temperature acanthite-like phase of Cu2S: Electronic and transport properties

Article

关键词: THERMOELECTRIC PERFORMANCE;    THERMAL-CONDUCTIVITY;    SOLAR-CELL;    COPPER;    SULFIDE;    POWER;    CHALCOCITE;   

DOI  :  10.1103/PhysRevB.105.075205

来源: SCIE

【 摘 要 】

The mobility and disorder in the lattice of Cu atoms as liquidlike behavior is an important characteristic affecting the thermoelectric properties of Cu2S. In this study, using a theoretical model called an acanthite-like structure for Cu2S at a low-temperature range, we systematically investigate the electronic structure, intrinsic defect formation, and transport properties by first-principles calculations. Therefore, previous experimental reports on the indirect band-gap nature of Cu2S were confirmed in this work with an energy gap of about 0.9-0.95 eV. As a result, the optical absorption coefficient estimated from this model also gives a potential value of alpha > 10(4) cm(-1) in the visible spectrum range. According to the bonding analysis and formation energy aspect, Cu vacancy is the most preferred defect to form in Cu2S, which primarily affects the conductive behavior as a p type, as experimentally observed. Finally, the transport properties of Cu2S system were successfully reproduced using an electron-phonon scattering method, highlighting the important role of relaxation time prediction in conductivity estimation instead of regarding it as a constant.

【 授权许可】

Free