A comparative study of GaAs/AlGaAs quantum well infrared photodetectors grown by molecular beam epitaxy and metal organic vapour phase epitaxy

Abstract

Quantum well infrared photodetector (QWIP) structures were grown by metal organic vapour phase epitaxy (MOVPE) and molecular beam epitaxy (MBE). These n-type QWIP structures were fabricated into devices. Inter-subband and inter-band transition energies were measured using photoresponse and photoluminescence spectroscopy. The carrier dynamics of one of the structures was analysed using temperature dependent up-conversion spectroscopy. These results were modelled with the solution of a three level system. Measurement of an n-type QWIP allows us to determine the inter-subband relaxation time of a p-type QWIP. The intersubband relaxation time of a p-type QWIP with 3 nm wide wells was determined to be 15 ps.