CVD-Grown Monolayer MoS₂ and GaN Thin Film Heterostructure for a Self-Powered and Bidirectional Photodetector with an Extended Active Spectrum

Abstract

Photodetector technology has evolved significantly over the years with the emergence of new active materials. However, there remain trade-offs between spectral sensitivity, operating energy, and, more recently, an ability to harbor additional features such as persistent photoconductivity and bidirectional photocurrents for new emerging application areas such as switchable light imaging and filter-less color discrimination. Here, we demonstrate a self-powered bidirectional photodetector based on molybdenum disulfide/gallium nitride (MoS 2 /GaN) epitaxial heterostructure. This fabricated detector exhibits self-powered functionality and achieves detection in two discrete wavelength bands: ultraviolet and visible. Notably, it attains a peak responsivity of 631 mAW −1 at a bias of 0V. The device's response to illumination at these two wavelengths is governed by distinct mechanisms, activated under applied bias conditions, thereby inducing a reversal in the polarity of the photocurrent. This work underscores the feasibility of self-powered and bidirectional photocurrent detection but also opens new vistas for technological advancements for future optoelectronic, neuromorphic, and sensing applications.

A Self-Driven Bidirectional Photocurrent Photodetector for Optically Controlled Logic Gates Utilizes a GaN-Nanowall Network

“…Furthermore, the absorption coefficient (α), calculated and illustrated in Figure (d), reveals that the grown GaN efficiently absorbs light in the UV region, with a peak value of 11 × 10 4 cm –1 . Moreover, Fabry–Perot resonance is in the visible areas, consistent with the epitaxial growth reported in existing literature . Field emission scanning electron microscopy (FESEM) analysis unveiled the morphology of the grown GaN, showcased in Figure (e).…”