Short-wavelength intersubband transitions in InGaAs/AlAs quantum well


Short-wavelength intersubband transitions in InGaAs/AlAs quantum well

Georgiev, N.; Semtsiv, M.; Dekorsy, T.; Eichhorn, F.; Bauer, A.; Helm, M.; Masselink, W. T.

InGaAs/AlAs quantum wells (QWs) have the potential for the development of new devices based on intersubband transitions, such as near-infrared detectors, ultra-fast switches and light emitters that operate at the communication wavelength of 1.55 mm.However, the increased strain accommodation in the InGaAs/AlAs system considerably affects the band offsets of these QW structures and the performance of the appropriate devices. We report structural and optical characterization of InxGa1-xAs/AlAs/InyAl1-yAs (x ~ 0.7, y ~ 0.55) QW structures grown on InP substrates. In these structures, we utilize the high conduction band offset provided by AlAs. An increased In content in the wells and in the InyAl1-yAs layers helps to compensate the large AlAs tensile strain. Additionally, the smaller InGaAs band gap results in a shift of the first G-like well subband to lower energies relative to the X-minimum in the barrier layers even in very narrow wells. Intersubband absorption at wavelengths shorter than 2.0 mm is observed in thin single QWs. Also presented are spectra of asymmetric coupled QWs and short-period superlattices.

Keywords: quantum well; strain structures; intersubband transitions

  • Lecture (Conference)
    Deutsche Physikalische Gesellschaft (DPG) - Tagung, Fachverband Halbleiterphysik, HL3.3, Dresden, 2003

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