Quantum well infrared photodetectors: design using the transfer matrix method

Abstract

This work demonstrates the use of the Transfer Matrix Method (TMM) to calculate the band structure of complex heterostructures in both valence and conduction band. The method shows versatility in obtaining the transmission coefficient, the energy states and the corresponding wave functions of a structure comprised of a large number of semiconductor layers. This ability is essential in Quantum Wells Infrared Photodetectors (QWIP) design using interband and intersubband transitions. To implement that, selected Hamiltonians are solved separately for conduction and valence bands. The method is validated comparing numerical results with analytical solutions of potentials such as Modified Posch-Teller. Furthermore, several results from the literature were reproduced by the TMM showing good agreement, with errors smaller than 5%. Finally, the method is used to estimate the responsivity wavelength peak of a QWIP using interband and intersubband transitions to detect near-, mid- and long infrared (NWIR, MWIR, LWIR). The comparison between measurements and the simulation showed good agreement, with an average error smaller than 3% for both interband and intersubband transitions. Those results indicate that the TMM is a suitable method to be used in QWIP design.