Giant Photovoltaic Effect and Self-Powered Photodetection in Lateral MoS₂ Homojunctions via Strong Interface Coupling.

Abstract

Lateral semiconductor homojunctions offer the advantages of perfect lattice matching and efficient carrier transport at the junctions, providing an ideal platform for high-performance optoelectronic devices. However, the fabrication of high-quality homostructures and the simultaneous realization of strong photovoltaic and photodetection performance remain challenging. In this work, we directly fabricated n⁺-n^- MoS₂ homostructures, consisting of partly pristine MoS₂ and partly MoS₂ stacked on a CrOCl insulator. Efficient charge transfer occurs at the MoS₂/CrOCl interface, as confirmed by a ∼200 meV band shift observed in micro-ARPES measurements, consistent with our DFT calculations. As a result, the portion of MoS₂ stacked on CrOCl can be modulated to p-type by controlling the gate voltage, in sharp contrast to the pristine MoS₂ region. Moreover, the n⁺-n^- MoS₂ homostructures exhibit an open-circuit voltage of 0.87 V, a detectivity exceeding 10¹² Jones, and a responsivity of 0.98 A/W without external stimuli, demonstrating both ultrahigh photovoltaic and self-powered photodetection capabilities. The results presented in our work provide a strategy for developing efficient optoelectronic devices based on two-dimensional homostructures.