n-ZnO:Ga/i-ZnO/p-Si heterojunction light emitting diodes fabricated on patterned Si substrates

Journal of Materials Science: Materials in Electronics 20, 1214–1218

https://doi.org/10.1007/s10854-009-9854-y

M. K. Choi, W. S. Han, Y. Y. Kim, B. H. Kong, H. K. Cho, J. H. Kim, H.-S. Seo, K.-P. Kim, and J.-H.Lee

Abstract

n-ZnO:Ga/i-ZnO/p-Si heterojunction light-emitting diodes were fabricated on patterned Si substrates with increased interface area where hole carriers were transported to the i-ZnO layer. The patterned Si substrates were prepared by electrochemical etching, and the n-type ZnO:Ga films were deposited by high-temperature sputtering. In the patterned LED, the lower breakdown and greater leakage current under a reverse bias was attributed to the formation of a high density of grain boundaries and random tilting of the c-axis. Compared to an LED without patterning, the patterned substrates resulted in approximately 75% improvement in the output power of visible emission, which was attributed to a 1.33-fold increase in the heterojunction area and the increase in grain boundary density due to grain tilting.