n-ZnO:Ga/i-ZnO/p-Si heterojunction light emitting diodes fabricated on patterned Si substrates
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.
KeywordsElectrochemical Etching Metal Insulator Semiconductor Deep Level Emission Metal Insulator Semiconductor Structure Increase Interface Area
This work at SKKU was supported by the Korea Research Foundation Grant funded by the Korean Government (MOEHRD) (KRF-2007-521-D00191) and by the Ministry of Knowledge Economy (MKE) and Korea Industrial Technology Foundation (KOTEF) through the Human Resource Training Project for Strategic Technology. This work at DGIST was supported by Korea Ministry of Education, Science and Technology (MEST) basic research fund.
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