This work presents a novel Gallium nitride (GaN) high-electron-mobility transistor (HEMT) based ultraviolet photodetector architecture integrating advanced material and structural design strategies to enhance detection performance and stability under room-temperature operation. The device is constructed on a high-thermal-conductivity silicon carbide (SiC) substrate and incorporates an n-GaN buffer, an indium nitride (InN) channel layer for improved electron mobility and two-dimensional electron gas (2DEG) confinement, and a dual-passivation scheme combining silicon nitride (SiN) and hexagonal boron nitride (h-BN). A p-GaN layer is embedded between the passivation interfaces to deplete the 2DEG in dark conditions. Lateral nickel (Ni) source and drain electrodes and a recessed gate positioned within the substrate ensure enhanced electric field control and noise suppression. Numerical simulations demonstrate that the integration of a hexagonal boron nitride (h-BN) interlayer within the dual passivation stack effectively suppresses the gate leakage current from typical literature values of the order of 10−7~A to approximately 10−10~A, highlighting its critical role in enhancing interfacial insulation. In addition, consistent with previous reports, the use of a silicon carbide (SiC) substrate offers significantly improved thermal management over sapphire, enabling more stable operation under UV illumination. The device demonstrates strong photoresponse under 360~nm ultraviolet (UV) illumination, high photo-to-dark current ratios (PDCR) of approximately 106, and tunable performance via structural optimization of p-GaN width between 0.40~μm and 1.60~μm, doping concentration from 5×1016~cm−3 to 5×1018~cm−3, and embedding depth between 0.060~μm and 0.068~μm.
@article{arxiv.2508.06782,
title = {GaN/InN HEMT based UV photodetector on SiC with hexagonal boron nitride passivation},
author = {Mustafa Kilin and Firat Yasar},
journal= {arXiv preprint arXiv:2508.06782},
year = {2025}
}