Dresden 2003 – scientific programme

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HL: Halbleiterphysik

HL 20: Halbleiterlaser III

HL 20.2: Talk

Tuesday, March 25, 2003, 11:15–11:30, BEY/154

Growth and characterization of In_0.32Ga_0.68As/In_0.32Ga_0.68P strain-compensated quantum cascade laser structure — •Mykhaylo Semtsiv, Mathias Ziegler, and Ted Masselink — Humboldt University Berlin, Invalidenstr. 110, 10115 Berlin, Germany

In_0.32Ga_0.68As/In_0.32Ga_0.68P strain-compensated quantum-cascade laser (QCL) structures with 3 quantum well active region have been grown by gas source MBE on GaAs. An investigation of the intersubband absorption in similar strain-compensated superlattices (SL) indicate that such a QCL with 4-nm quantum wells in the active region will result in mid-infrared emission at 6.2 µm. From these absorption data, the effective masses and conduction band discontinuities were determined. The temperature dependence of electron miniband transport in the injection regions has been studied through DC I-V characteristics under positive and negative bias. Due to a small conduction band offset between In_0.32Ga_0.68P and GaAs, thermionic emission over the SL dominates at room temperature, which provides almost symmetric transport in both directions. Low temperature transport, however, is strongly asymmetric and shows typical I-V shape for QCLs. A PL study of the biased active region provides information on carrier distribution change in electric field.

This work was supported by the Deutsche Forschungsgemeinschaft within Forschergruppe 344.