Improvement of diodes performance with a multiple-pair buffer layer by MOCVD

The GaN home-junction light-emitting diodes (LEDs) with a multiple-pair buf fer layer (MBL) were grown by metalorganic vapor phase epitaxy on sapphire substrates. Each pair of the buffer layer consists of a 300 Angstrom thick GaN nucleation layer grown at a low temperature of 525 degreesC and a 4 m t hick GaN epitaxial layer grown at a high temperature of 1025 degreesC. It i s found that the GaN LEDs with a three-pair buffer layer will exhibit a low turn-on voltage, stronger electroluminescence intensity and higher light-o utput power as compared to the conventional growth without a buffer layer. This is attributed to the effective reduction in the propagation of defects and dislocations near the p-n junction for the LEDs with MBL. (C) 2001 Els evier Science B.V. All rights reserved.