SKM 2021 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 23: Focus Session: Highlights of Materials Science and Applied Physics III (joint session DS/HL)

HL 23.2: Vortrag

Freitag, 1. Oktober 2021, 11:30–11:45, H1

Pyramid formation by etching of InGaN/GaN quantum well structures grown on N-face GaN for nano optical light emitters — •Uwe Rossow, Savutjan Sidikejiang, Samar Hagag, Philipp Henning, Rodrigo de Vasconcellos Lourenco, Heiko Bremers, and Andreas Hangleiter — TU Braunschweig, Inst. f. Angewandte Physik

While growth processes of In_xGa_1-xN/GaN quantum well structures on the Ga-face of GaN buffer layers are already optimized to obtain high quantum efficiency, the growth on N-face has gained momentum only in the last years. Compared to Ga-face In_xGa_1-xN layers are more stable on N-face and the surface can easily be structured by wet chemical etching, which usually leads to the formation of pyramids on the surface. This allows a new way to realize nano optical light emitters which offers the possibility to produce structures with similar emission properties. First we grow In_xGa_1-xN/GaN (single or multi) quantum well structures on N-face GaN. In a second step pyramids are formed by KOH etching. We demonstrate that pyramids with smooth side facets of the type (1101) and sharp tips in the nanometer range can be achieved without any sign of damage. TEM reveals that InGaN quantum dot-like structures are present in the pyramids and in photoluminescence narrow emission lines are observed. The etching process depends on electrolyte composition and temperature, defects at the surface and surface morphology. A better control of this process is required to achieve reproducible nano structures.