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HL: Fachverband Halbleiterphysik

HL 49: Optical Properties

HL 49.3: Vortrag

Donnerstag, 25. März 2010, 10:00–10:15, H14

Disorder in Ga(N,As,P)/GaP MQW structures — •Christian Karcher, Tobias Bertram, Bernardette Kunert, Kerstin Volz, Wolfgang Stolz, Kakhaber Jandieri, Sergei Baranovskii, and Wolfram Heimbrodt — Dept. Physics and Material Sciences Center, Philipps- University of Marburg, Germany

The incorporation of nitrogen into III-V semiconductors has an enormous impact onto the emission characteristics of the host material. We examine these features in pseudomorphically grown multiple-quantum-well heterostructures of the dilute nitride Ga(NAsP)/GaP material system by means of modulated reflectance, photoluminescence- (PL) and PL excitation-spectroscopy. By identifying both the absorption and emission characteristics of the system from 10K up to room temperature, we observe a large stokes shift originating from deep traps formed by nitrogen. The complex temperature behaviour of the resulting emission can be understood in detail by theoretically modelling hopping processes in an exponential distribution of localised states within the band gap. This model explains the s-like temperature shift and the linewidth broadening of the emission as well as the high stokes shift up to room temperature.