4H SiC high power photoconductive semiconductor switching devices were fabricated. A highly doped n+-GaN subcontact epilayer was grown on SiC by organometallic vapor phase epitaxy in order to improve ohmic contact and avoid contact damage or degradation due to current filamentation, under high power operation. With an n+-GaN subcontact layer, the contact resistance was reduced and current crowding alleviated. Therefore the electrodes were not damaged or degraded at high power operation. Photocurrent up to 200 A and breakdown voltage up to 2900 V have been observed for the devices.