Regensburg 2013 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 72: Focus Session: Extended defects in semi- and nonpolar GaN I
HL 72.8: Talk
Thursday, March 14, 2013, 12:45–13:00, H13
InGaN/GaN based semipolar light emitting diodes — •Junjun Wang1, Matthias Hocker2, Robert Leute1, and Ferdinand Scholz1 — 1Institute of Optoelectronics, Ulm University, Germany — 2Institute of Quantum Matter, Ulm University, Germany
Non- and semipolar III-nitrides are promising to fabricate highly efficient light-emitting devices due to a reduced piezoelectric field leading to an increased overlap of electron and hole wavefunctions. In our research, three-dimensional stripes are realized by selective area growth on patterned masks providing semipolar surfaces. We focused on improving the electrical and optical performance of the stripe light emitting diodes with the semipolar InGaN/GaN quantum wells (QWs). Defects are generated at the tip via strain relaxation during the semipolar InGaN/GaN QWs resulting in a large leakage current. It is reduced from ~5mA to ~0.3mA at a reverse bias of 5V by including a 50nm p-GaN layer before the p-AlGaN electron blocking layer (EBL). Mg doping induces lateral growth in the ~50nm p-GaN layer leading to a plateau at the tip. Under a suitable epitaxial condition, AlGaN EBL grows more vertically recovering the sharp tip with an AlGaN triangle to block the leakage current there. The growth of the undoped GaN between the QWs and p-(Al)GaN was controlled to avoid any plateau or current crowding at the tip.