CHARACTERIZATION OF GAAS INGAAS QUANTUM-WELLS USING PHOTOCURRENT SPECTROSCOPY/

We report on characterization studies of high quality metal-organic va por phase epitaxy and molecular beam epitaxy grown GaAs/InGaAs quantum wells, set within p-i-n diodes, to determine the well widths, indium mole fractions, and conduction band offset. We present photocurrent sp ectra containing a larger number of transitions than revealed in photo luminescence or photoluminescence excitation experiments. The energies of these transitions have been modeled using a theoretical characteri zation tool known as ''contouring,'' which is used in this strained sy stem for the first time. This has enabled determination of the conduct ion band offset in GaAs/InGaAs quantum wells, to a value between 0.62 and 0.64, for a range of indium fractions between 0.155 and 0.23. As a final, additional check on our results, we compare the field dependen ce of the e1-hh1 exciton transition energy with our theoretical calcul ations and find good agreement. (C) 1996 American Institute of Physics .