Berlin 2012 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 24: Poster Session: Ge/Si/SiC / III - V Semiconductors

HL 24.10: Poster

Monday, March 26, 2012, 16:00–19:00, Poster D

Growth mechanisms of thin GaN on AlN — •Konrad Bellmann, Abdul Kadir, Markus Pristovsek, and Michael Kneissl — TU Berlin, Berlin, Deutschland

GaN based QD devices are very promising to reach single photon emission at room temperature, because of their feasibility of higher electron confinement. The lattice mismatch of GaN and AlN is about 2.5%. However, overgrowth of AlN by GaN results in 2D growth at normal growth conditions. In order to achieve QDs in Stranski-Krastanov mode, a small parameter window at low V/III ratio with additional annealing step is needed.

An additional challenge for QD growth is smooth AlN surfaces. Therefore, we have varied the V/III ratio during AlN growth. Due to the high binding energy of AlN, aluminum has a low diffusibility on the surface. With lower ammonia partial pressure higher aluminum ad atom mobility was achieved, resulting in smoother surfaces. High V/III ratio results in spiral growth.