Electrochemical fabrication and optoelectronic properties of hybrid heterostructure of CuPc/porous GaN

Ultrahigh Sensitivity Graphene/Nanoporous GaN Ultraviolet Photodetectors

Integration of graphene with three-dimensional semiconductors can introduce unique optical and electrical properties that overcome the intrinsic limitation of the materials. Here, we report on the high sensitivity ultraviolet (UV) photodetectors based on monolayer graphene/nanoporous GaN heterojunctions. By investigating the reflectivity, photoluminescence, and Raman spectral characteristics of nanoporous GaN, we find that the increase in the porosity can help to improve its optical properties. The device based on the highest-porosity nanoporous GaN demonstrates rapid and linear response to UV photons, with an ultrahigh detectivity of 1.0 × 10¹⁷ Jones and a UV-visible rejection ratio of 4.8 × 10⁷ at V = -1.5 V. We attribute such high sensitivity to the combination of the significantly enhanced light harvesting of high-porosity nanoporous GaN and the unique UV absorption, high mobility, and finite density of states of the monolayer graphene. The high performance together with a simple and low-cost fabrication process endow these graphene/nanoporous GaN heterojunctions with great potential for future selective detection of weak UV optical signals.

High-detectivity ultraviolet photodetectors based on laterally mesoporous GaN

Photodetectors for the ultraviolet (UV) range of the electromagnetic spectrum are in great demand for several technologies, but require the development of novel device structures and materials. Here we report on the high detectivity of UV photodetectors based on well-ordered laterally mesoporous GaN. The specific detectivity of our devices under UV-illumination reaches values of up to 5.3 × 10¹⁴ Jones. We attribute this high specific detectivity to the properties of the mesoporous GaN/metal contact interface: the trapping of photo-generated holes at the interface lowers the Schottky barrier height thus causing a large internal gain. High detectivity along with a simple fabrication process endows these laterally mesoporous GaN photodetectors with great potential for applications that require selective detection of weak optical signals in the UV range.