Insights on the optoelectronic properties in two-dimensional Janus lateral In2SeTe/Ga2STe heterostructure

In this paper, the lateral heterostructures combined with monolayer Janus compounds Indium selenide telluride (In2SeTe) and Gallium sulfide telluride (Ga2STe) are investigated by first-principles calculations. Phonon spectrum analysis indicates that two Janus lateral In2SeTe/Ga2STe heterostructures combined in different ways can be formed steadily. The calculations show that two heterostructures exhibit type-II band alignment, which is key to the separation of photocarriers. The lateral In2SeTe/Ga2STe heterostructure has a direct band gap of 1.50 eV, in line with high-performance excitonic solar cells. The ternary systems show higher optical absorption coefficient in the visible light region and better two-dimensional electron mobility than the binary lateral heterostructure InS/InSe. Finally, the photoelectric conversion efficiency of the Janus In2SeTe/Ga2STe lateral heterostructure reaches a competitive 21%. Thus, the high conversion efficiency and suitable direct bang gap as well as the perfect band alignment may make the In2SeTe/Ga2STe lateral heterostructure a promising material for optoelectronics devices.