High ambipolar mobility in cubic boron arsenide revealed by transient reflectivity microscopy
Shuai Yue, Fei Tian, Xinyu Sui, Mohammadjavad Mohebinia, Xianxin Wu, Tian Tong, Zhiming Wang, Bo Wu, Qing Zhang, Zhifeng Ren, Jiming Bao, Xinfeng Liu
Abstract
Semiconducting cubic boron arsenide (c-BAs) has been predicted to have carrier mobility of 1400 square centimeters per volt-second for electrons and 2100 square centimeters per volt-second for holes at room temperature. Using pump-probe transient reflectivity microscopy, we monitored the diffusion of photoexcited carriers in single-crystal c-BAs to obtain their mobility. With near-bandgap 600-nanometer pump pulses, we found a high ambipolar mobility of 1550 ± 120 square centimeters per volt-second, in good agreement with theoretical prediction. Additional experiments with 400-nanometer pumps on the same spot revealed a mobility of >3000 square centimeters per volt-second, which we attribute to hot electrons. The observation of high carrier mobility, in conjunction with high thermal conductivity, enables an enormous number of device applications for c-BAs in high-performance electronics and optoelectronics.