Self-powered broadband photodetection enabled by facile CVD-grown MoS2/GaN heterostructures

Achieving self-powered photodetection without biasing is a notable challenge for photodetectors. In this work, we demonstrate the successful fabrication of large-scale van der Waals epitaxial molybdenum disulfide (MoS2) on a p-GaN/sapphire substrate using a straightforward chemical vapor deposition (CVD) technique. Our research primarily centers on the characterization of these photodetectors produced through this method. The MoS2/GaN heterojunction photodetector showcases a broad and extensive photoresponse spanning from ultraviolet A (UVA) to near-infrared (NIR). When illuminated by a 532 nm laser, its self-powered photoresponse is characterized by a rise time (tau(r)) of similar to 18.5 ms and a decay time (tau(d)) of similar to 123.2 ms. The photodetector achieves a responsivity (R) of similar to 0.13 A W-1 and a specific detectivity (D*) of similar to 3.8 x 10(10) Jones at zero bias. Additionally, while utilizing a 404 nm laser, the photodetector reaches a maximum R and D* of similar to 1.7 x 10(4) A/W and similar to 1.6 x 10(13) Jones, respectively, at V-b = 5 V. The operational mechanism of the device can be explained by the diode characteristics involving a tunneling current in the presence of reverse bias. The exceptional performance of these photodetectors can be attributed to the pristine interface between the CVD-grown MoS2 and GaN, providing an impeccably clean tunneling surface. Additionally, our investigation has unveiled that MoS2/GaN heterostructure photodetectors, featuring MoS2 coverage percentages spanning from 20% to 50%, exhibit improved responsivity capabilities at an external bias voltage. As a result, this facile CVD growth technique for MoS2 photodetectors holds significant potential for large-scale production in the manufacturing industry.

Automated summary

In this study, large-scale MoS2/GaN heterojunction photodetectors were successfully fabricated using chemical vapor deposition. The photodetectors exhibited a broad photoresponse range and self-powered photoresponse characteristics. Additionally, the coverage percentage of MoS2 was found to affect the responsivity capabilities of the detectors. This facile growth technique holds potential for large-scale production in the manufacturing industry.