Improved characteristics of GaN-based light-emitting diodes by distributed Bragg reflector grown on Si

Abstract

We report the improved characteristics of GaInN light-emitting diodes (LEDs) on Si substrates by a distributed Bragg reflector (DBR). The DBR-based GaInN multi quantum-well LED structures were grown on n-Si (111) substrates using a conventional horizontal metalorganic chemical vapor deposition method. The number of Al0.3Ga0.7N/AlN pairs in the DBR was changed from 1 to 5. The measured PL peak intensity ratio agrees well with the calculated value. In an EL measurement, the output power increases with an increase in the number of pairs in the DBR (less than 3 pairs). The light output power of a 3-pair DBR-based LED is approximately twofold larger than that of a non-DBR-based LED. However, it significantly decreases in a 5 pair of DBR, because of a crack formation. Although the suppression of crack formation remains a problem, the DBR is still very promising for the fabrication of high-performance LEDs on Si. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)