Improvement of light extraction efficiency in n-ZnO:Ga/I-ZnO/p-Si heterojunction LED using truncated pyramid patterned Si substrates

Abstract

n-ZnO:Ga/i-ZnO/p-Si heterojunction light-emitting diodes (LEDs) were fabricated using patterned Si substrates having larger junction area than normal flat ones where recombined photons are generated. The patterned p-type Si substrates were prepared by anodization which is very cost competitive method, and the n-type ZnO:Ga films were deposited by high-temperature sputtering. The truncated patterning of the substrates resulted in approximately 75 % improvement in output power compared with the LED without the pattern, which was attributed to a 1.33-fold increase in the junction area through patterning. © The Electrochemical Society.