摘要
Molybdenum disulfide (MoS )-based phototransistors are attractive for optical electronics in a large-scale size, such as transparent touch screens. However, most of the work done over the past decade has been on an opaque SiO ∕Si wafer with a small size (micrometer to millimeter). In this work, a large-scale multilayer MoS -based phototransistor has been fabricated on a transparent freestanding gallium nitride (GaN) wafer using a scalable chemical vapor deposition method. Due to the near lattice match and small thermal expansion mismatch between GaN and MoS , the as-grown multilayer MoS -on-GaN film shows high material quality in terms of low full width at half-maximum (∼5.16 cm ) for the E Raman mode and a high absorption coefficient (∼10 cm ) in the wavelength range of 405–638 nm. Under a wavelength of 405 nm at an incident power of 2 mW and applied voltage of 9 V, the fabricated MoS -on-GaN phototransistor achieved a maximum responsivity of 17.2 A/W, a photocurrent gain of 53.6, and an external quantum efficiency of 5289%, with specific detectivity (∼10 –10 Jones) and low noise equivalent power (10 –10 W∕Hz ) in the visible range of 405–638 nm. A typical response time of 0.1–4 s in the ambient air has also been recorded for the demonstrated MoS -on-GaN phototransistor. Our work paves a technologic stepping stone for MoS -based phototransistors for multifunctional transparent and touch-based optoelectronics in the future.