# High sub-bandgap response and fast switching enabled by thermal quenching in carbon-doped semi-insulating GaN Source: [High sub-bandgap response and fast switching enabled by thermal quenching in carbon-doped semi-insulating GaN]() Collection index: [llms.txt]() Data updated: 2026-06-17T05:00:21.724Z Authors: Jiahao Dong, Auditee Majumder Momo, Austin Fehr, Sanam SaeidNahaei, Pramod Reddy, Ronny Kirste, Zlatko Sitar, Ram\\'on Collazo, Selim Elhadj Published: 2026-02-27T03:27:56.000Z ## Abstract Carbon-doped GaN is a promising material for sub-bandgap triggered optical switches. When incorporated in GaN, carbon introduces deep compensating centers that enable defect-mediated extrinsic photoconductivity. Here, we investigate the optical responsivity and switching kinetics of semi-insulating carbon-doped GaN actuated by sub-bandgap blue illumination. A high ON/OFF ratio exceeding $\\mathrm{10^7}$ is achieved under low-irradiance 405-nm excitation. Temperature-dependent transient measurements reveal that the photocurrent decay is thermally quenched above a crossover temperature of ~300 K. This behavior is attributed to hole-emission-assisted recombination. The extracted activation energies vary across samples; a commonly observed value of ~0.83 eV is attributed to the $\\mathrm{C\_N}$ defect. Notably, when heating above the crossover temperature, thermal quenching accelerates the photocurrent decay by up to a factor of five, enabling significantly faster switching. ## Recorded benchmark results A research result applies to its stated dataset, split, metric and evaluation configuration. Compare like-for-like settings, preserve the metric's unit and direction, and distinguish paper-reported results from independent reproduction. The best result recorded here is not a claim of exhaustive, current global coverage. ## Original sources and implementation [Original paper]() [PDF]()