Photoluminescence Study of As Doped p-type HgCdTe Absorber for Infrared Detectors Operating in the Range up to 8 µm

Abstract

A HgCdTe photodiode grown by chemical vapor deposition (MOCVD) on a GaAs substrate operating in the long-wave infrared (LWIR) range was characterized using photoluminescence (PL) measurements. At high temperatures, the PL spectrum originates from a free-carrier emission and might be fitted by a theoretical expression being the product of the density of states and the Fermi–Dirac distribution. At low temperatures, the PL spectrum consists of multiple emission peaks that do not originate solely from the energy gap. Such spectra are not unambiguous to interpret due to the prominence of different optical transitions. Spectral response (SR) measurements were used to determine the energy gap (Eg) and extract the band-to-band transition from the PL spectra. PL peaks visible within the band gap were fitted by a Gaussian distribution.