Study Of GaN-based Green LED Opto-electronic Properties Grown Of Si Substrate

GaN based green light emitting diodes has been demonstrated a large potential for applications in full-color display and solid-state lighting.Because of high In fraction in the quantum well, green light emitting diodes has suffered more serious polarization and strain effects than blue light emitting diodes.The efficiency loss of the green light emitting diodes restrict the application of light emitting diodes.Recently,improving green light emitting diodes performance becoming a major focus of research.We grown green light emitting diodes on Si(111) substrates with P-AlGaN electron blocking layer (EBL) which has different Al fration.The result show that the quantum efficiency has a diversity changing rule versus the current density. At lower current density, the light emitting diodes with higher Al fraction have a lower quantum efficiency droop velocity. However, the situation is inversed at a larger current.This is attributed to complicated mechnism when the electron and hole recombination in the quantum wells.We report the new developments in green light emitting diodes.Packaged 500μm×500μm chips emit up to 23mW at 60mA.To our knowledge these are the highest brightness and efficiency values of green light emitting diodes grown on si substrate in literature.The reliability research showes:under 60mA within 2005 hour aging process,the light output power decrease 11.6%,the change of the threshold voltage value less than 0.1v.This demonstrated the green light emitting diodes has an bright forcast for the applications.This project supported by the Changjiang Scholars and Innovative Reserch Team in University of Ministry of Education of China (Grant No.IrT0730), National High Technology and Development Program of China (Grant No.YC09A024) and Postgraduate Innovation fund of Jiangxi Province (Grant NO.YC09A024).