Analysis of temperatue dependence of nitride-based quantum cascade detectors

Abstract

QCDs are emerging technology which has shown to encompass wavelengths from near-infrared to the THz region. The design of QCDs has proven to be robust and reliable. Especially in the MIR range around 4 to 16 m, well-established semiconductor material systems and processing procedures are available. MIR range also holds signature absorption peaks for some greenhouse gases that has significant environmental and chemical application. Again nitride based material system demonstrate superior performance in terms of large LO-phonon energy, current capacity, electron mobility, break-down voltage, and e ciency for power module and photovoltaic applications. In this thesis, a nitride based material system simulator is developed using the inherent strain and polarization e ect of the nitride material. The simulator solves the band structure and energy values of a nitride based quantum cascade structure. Moreover two designs of nitride based QCD operating in the mid-infrared region are presented along with a detail transport and performance analysis. This thesis also attempts to study important parameters of the nitride based detectors as function of detector temperature. The strongly varying device resistance and the drop in responsivity with temperature of the mid-infrared quantum cascade detectors are numerically calculated based on a model describing LO-phonon assisted transitions between the di erent involved states of the quantum cascade.