Dresden 2003 – wissenschaftliches Programm

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HL: Halbleiterphysik

HL 53: Heterostrukturen

HL 53.6: Vortrag

Freitag, 28. März 2003, 13:00–13:15, BEY/118

Minority Carrier Lifetime Investigation on InAs/(GaIn)Sb Short Period Superlattices — •Christian Pfahler, Frank Fuchs, Johannes Schmitz, Quankui Yang, Robert Rehm, and Wilfried Pletschen — Fraunhofer-Institut fuer Angewandte Festkoerperphysik (IAF), Tullastrasse 72, D-79108 Freiburg, Germany

InAs/(GaIn)Sb short-period superlattices (SL) grown by molecular beam epitaxy (MBE) show a broken-gap type II band alignment. The effective band gap can be tailored ranging from the far-infrared (IR) to the mid-IR wavelength region by changing the In molar fraction of the (GaIn)Sb layers and the individual layer thicknesses. The InAs/(GaIn)Sb materials system is thus considered as a promising candidate to establish an IR detector system based on III-V growth and processing technology. A crucial quantity for the evaluation of the performance of a minority carrier device, e.g. an infrared photodiode, is the minority carrier lifetime. We report on the investigation of the lifetime on p- and n-doped SLs performing quantitative photoconductivity measurements. At 77 K values between 10 and 100 ns are found for the long-wavelength material with band gap energies around 120 meV. For SLs showing n-type conductivity a weak temperature dependence is found in the temperature range between 60 and 120 K, while p-type SLs show a strong thermally activated decrease of the lifetime, suggesting the presence of a deep defect level.