Growth of Semi‐Insulating Mn–GaN by the Near‐Equilibrium Ammonothermal Method and Its Application to a High‐Voltage Photoconductive Semiconductor Switch

This article presents manganese‐doped gallium nitride (Mn–GaN) bulk crystals with various manganese concentrations grown by the near‐equilibrium ammonothermal method and characterization of photoconductive semiconductor switches (PCSS) fabricated with them. The concentration of Mn in GaN affects the coloration of the crystal as well as the resistivity. Microstructures evaluated with mapping of full width at half maximums of X‐ray rocking curves from 002 and 201 diffractions do not show obvious degradation for manganese concentrations lower than mid‐10 19 cm −3 . The optical absorption spectrum shows a broad peak at about 820 nm and a large band tail in the conduction band. This article demonstrates a PCSS fabricated with a bulk Mn–GaN crystal with a blocking voltage of 12 kV and a fast (≈10 ns) switching response having a peak current of 120 A under irradiation of 532 nm, 3 mJ laser pulse. Also demonstrated is a preliminary reliability test of 100 shots of laser irradiation without obvious degradation of the device.