Enhancement of responsivity and a self-powered on-chip LNOI integrated BiTe photodetector array.

The topological insulator BiTe possesses an extraordinary optoelectronic property for wide-band optoelectronics device applications. In this study, we demonstrate a high-responsivity and self-powered on-chip lithium niobate on insulator (LNOI) waveguide-integrated BiTe photodetector array operating at 1550 nm. Enhancement of responsivity is attributed to the decreased BiTe/Au contact resistance, which is facilitated by electrothermal annealing. The post-electrothermal annealed on-chip photodetector was demonstrated a photocurrent response increased by four orders of magnitude, reaching as high as 5.5 µA. It features a photoresponsivity of 60 mA/W and a response time of 10 µs. The uniform performance of the fabricated BiTe photodetector arrays integrated with 4× multi-mode interference on the same LNOI photonic chips proves its potential for applications in high-efficiency optical communication, optical computing, and large-scale data processing.