Published online by Cambridge University Press: 22 February 2011
Phototransmittance has been used to investigate several pseudomorphic Al0.32Ga0.68As/In0.15Ga0.85As/GaAs high electron mobility transistor structures, with different values of the electron density ns. A lineshape analysis of the ground state transition made it possible to estimate ns, at room temperature. A signal from the Fermi-edge singularity (a manybody effect), was observed at low temperatures and the dependence of its intensity on temperature and electron density was examined.