Photoluminescence analysis of InAlAs-InGaAs HFET material with varied placement of heavy delta-doping

Low temperature photoluminescence (PL) has been used to characterize InAlAs/InGaAs/InP heterojunction field-effect transistor (HFET) structure material. A phenomenological lineshape model has been applied to the PL spectrum to derive energy levels and the position of the Fermi-energy and hence the channel carrier concentration. The data is compared with results from low-temperature Hall and Shubnikov-de Hans (SdH) measurements, and fit with a charge-control model of the conduction band. Values for the sheet density are derived from PL for channel-doped structures where SdH measurements are difficult. Changes in the quantum well symmetry through variations in the dopant distribution are shown to be reflected in the PL lineshape.