Theoretical Modeling of Linear Absorption Coefficients in Si/Si1-xGex MultipleQuantum Well Photodetectors

摘要

Si/Sisub(1-x)Gesubx MQW Infrared Photodetectors offer the promise of normalincidence photodetection tunable over the range of 3-12 micrometers wavelength range at temperatures above 40 K. This system is aftractive because the Sisub(1-x)Gesubx offers greater compatibility with existing Si based signal processing circuitry. Band structures, momentum matrix elements and linear absorption coefficients are computed using a Luftinger-Kohn k/p analysis for Si/Sisub(1-x)Gesubx quantum wells grown in the 110 direction. The absorption coefficient as a function of energy and wavelength is calculated by two methods: a delta function fit to intersubband transitions, and a Lorentzian fit to intersubband transitions. Calculations were performed for parallel as well as normally incident radiation and the resulting absorption spectra are in good agreement with experimental observations.