2012 Volume 132 Issue 8 Pages 1261-1264
A p-GaN semiconductor is the more suitable photocathode material than a p-GaAs semiconductor, because a p-type semiconductor with wide band gap has large vacuum level shift caused by surface band bending. We measured quantum yield degradation and quantum yield spectrum of a p-GaN photocathode with an NEA surface. The p-GaN photocathode had the process of quantum yield degradation from the extraction of photocurrent and the residual gas, it is found to be important to suppress backs-pattering due to the increase of background pressure. From the dependence of quantum yield of the p-GaN photocathode on excitation wavelength, the quantum yield spectrum rapidly increased around the band gap of GaN as expected.
The transactions of the Institute of Electrical Engineers of Japan.C
The Journal of the Institute of Electrical Engineers of Japan