Electrical and light-emitting properties from (111)-oriented homoepitaxial diamond p-i-n junctions

We have succeeded in fabricating a (111)-oriented diamond p-i-n junction with high crystalline quality intrinsic layer and with low series resistance. The series resistance of this diamond p-i-n junction was improved by decreasing the resistivity and specific contact resistance of n-type layer, which is allowed to inject higher current while maintaining lower junction temperature. Current density-voltage characteristics showed a rectification ratio of 10(6) at +/- 15 V at room temperature. A clear ultraviolet emission at around 235 nm due to free exciton recombination was observed at a forward current, while the broad visible light emission from deep levels was significantly suppressed. Moreover, stronger excitonic emission by two orders of magnitude than that of (001)-oriented diamond p-i-n junctions with high series resistance was realized. (C) 2009 Elsevier B.V. All rights reserved.