skip to main content

Title: High-power low-droop violet semipolar (303{sup ¯}1{sup ¯}) InGaN/GaN light-emitting diodes with thick active layer design

Devices grown on nonpolar and semipolar planes of GaN offer key performance advantages over devices grown on the conventional c-plane, including reduced polarization fields. This allows for a wider design space on semipolar planes for light emitting diodes (LEDs) to address the problem of efficiency droop at high current densities. LED structures with very thick (10–100 nm) InGaN single-quantum-well/double heterostructure active regions were grown using conventional metal organic chemical vapor deposition on semipolar (303{sup ¯}1{sup ¯}) free-standing GaN substrates and processed and packaged using conventional techniques. Simulated band diagrams showed reduced polarization fields on the (303{sup ¯}1{sup ¯}) plane. The calculated critical thickness for misfit dislocation formation is higher on the (303{sup ¯}1{sup ¯}) plane than on other semipolar planes, such as (202{sup ¯}1{sup ¯}), allowing for thicker active regions than our previous work to further reduce droop. The higher critical thickness was confirmed with defect characterization via cathodoluminescence. A trend is demonstrated in lower efficiency droop for devices with thicker active regions. Thermal droop characteristics of these devices are also presented. These observed results were utilized to demonstrate over 1 W of output power at a current density of 1 kA/cm{sup 2} from a single 0.1 mm{sup 2} LED device.
Authors:
; ;  [1] ;  [2] ;  [3] ; ;  [1] ;  [4]
  1. Materials Department, University of California, Santa Barbara, California 93106 (United States)
  2. Department of Electrical and Computer Engineering, University of California, Santa Barbara, California 93106 (United States)
  3. Optoelectronic Laboratory, Mitsubishi Chemical Corporation, 1000 Higashi-Mamiana, Ushiku, Ibaraki 300-1295 (Japan)
  4. (United States)
Publication Date:
OSTI Identifier:
22310640
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 105; Journal Issue: 17; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CATHODOLUMINESCENCE; CHEMICAL VAPOR DEPOSITION; CRYSTAL DEFECTS; CURRENT DENSITY; DISLOCATIONS; EFFICIENCY; ELECTRONIC STRUCTURE; GALLIUM NITRIDES; INDIUM COMPOUNDS; LIGHT EMITTING DIODES; ORGANOMETALLIC COMPOUNDS; POLARIZATION; QUANTUM WELLS; SIMULATION; SUBSTRATES; THICKNESS