26 July 1999 Measurement of GaAs/(Al,Ga)As materials parameters for QWIP design calculations
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Abstract
We report the result of intersubband absorption measurement on a series of doped quantum-well samples and the determination of both the nonparabolicity parameters and the conduction band/valence band offset ratio of the GaAs/(AlGa)As material system. Absorption spectra were obtained in an FTIR spectrometer for samples with nominal quantum-well widths of 4.0, 4.5, 5.0, 7.5, 10.0, and 15.0 nm and for a series of miniband-transport quantum-well IR photodetectors. X-ray diffraction was used to determine quantum well and barrier thicknesses and the Al mole fraction x of the (Al,Ga)As barrier layers. Absorption measurements were made at temperatures of 295 K and 77 K. An empirical two-band model with an energy-dependent effective mass was used to calculate energy levels, transition energies, and spectral lineshapes for the quantum-well structures. Parameter values for nonparabolicity and band offset ratio were determined by comparison of calculated transition energies to measured spectral data.
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Richard P. Leavitt, Richard P. Leavitt, Daniel W. Beekman, Daniel W. Beekman, John W. Little, John W. Little, } "Measurement of GaAs/(Al,Ga)As materials parameters for QWIP design calculations", Proc. SPIE 3698, Infrared Technology and Applications XXV, (26 July 1999); doi: 10.1117/12.354569; https://doi.org/10.1117/12.354569
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