Wafer-scale 2H-MoTe2/perovskite quantum dot phototransistors with light-modulated ambipolar transport

Abstract

Here, we report wafer-scale 2H-MoTe2/perovskite quantum dot phototransistors that exhibit light-modulated ambipolar charge transport. CsPbBr3 quantum dots are monolithically integrated with 2H-MoTe2 films grown by cold-wall chemical vapor deposition, enabling uniform device fabrication over entire 2-in. wafer. Under 405 nm illumination, the devices display pronounced threshold-voltage shifts and polarity-dependent transfer characteristics, allowing gate-tunable ambipolar operation with well-defined p- and n-channel conduction. The photoresponse is predominantly governed by an interfacial photogating mechanism, in which photoexcited electrons trapped at the quantum-dot/MoTe2 interface generate a negatively charged layer that capacitively modulates the MoTe2 channel. This mechanism manifests quantitatively as asymmetric subthreshold slopes for hole and electron transport, illumination-enhanced carrier mobilities, threshold-voltage shifts of up to ∼0.35 V, and a photoresponsivity reaching ∼2.8×102 A/W at low optical power. Statistical analysis of structural and electrical parameters further confirms excellent wafer-scale uniformity. These results establish interfacial photogating-enabled, light-modulated ambipolar transport in mixed-dimensional heterostructures and underscore the potential of wafer-scale 2D/perovskite platforms for scalable low-power optoelectronic applications.