Pressure‐Dependent Behavior of Defect‐Modulated Band Structure in Boron Arsenide

• Published in: Advanced materials (Weinheim) Vol. 32; no. 45; pp. e2001942 - n/a
• Main Authors: Meng, Xianghai, Singh, Akash, Juneja, Rinkle, Zhang, Yanyao, Tian, Fei, Ren, Zhifeng, Singh, Abhishek K., Shi, Li, Lin, Jung‐Fu, Wang, Yaguo
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 01.11.2020
• Subjects: Arsenides; band structure; Boron; boron arsenide, high pressure; Conduction bands; Electronic devices; Electronic properties; Energy gap; Energy levels; impurities; Intermetallic compounds; Mass spectrometry; Materials science; Mathematical analysis; Photoluminescence; Pressure dependence; Thermal conductivity; Thermal management; Transport properties
• ISSN: 0935-9648; 1521-4095; 1521-4095
• DOI: 10.1002/adma.202001942

The recent observation of unusually high thermal conductivity exceeding 1000 W m−1 K−1 in single‐crystal boron arsenide (BAs) has led to interest in the potential application of this semiconductor for thermal management. Although both the electron/hole high mobilities have been calculated for BAs, there is a lack of experimental investigation of its electronic properties. Here, a photoluminescence (PL) measurement of single‐crystal BAs at different temperatures and pressures is reported. The measurements reveal an indirect bandgap and two donor–acceptor pair (DAP) recombination transitions. Based on first‐principles calculations and time‐of‐flight secondary‐ion mass spectrometry results, the two DAP transitions are confirmed to originate from Si and C impurities occupying shallow energy levels in the bandgap. High‐pressure PL spectra show that the donor level with respect to the conduction band minimum shrinks with increasing pressure, which affects the release of free carriers from defect states. These findings suggest the possibility of strain engineering of the transport properties of BAs for application in electronic devices. Impurities and defects play a significant role in the thermal, electrical, and optical properties of boron arsenide (BAs). Si/C donor–acceptor pair transitions are identified within the indirect bandgap. With high pressure/strain applied by a diamond anvil cell, the intrinsic band structure of BAs can be modified, suggesting potential applications in electronic devices by strain.