High Pressure Magneto-Optical Studies of Novel Localized States in Compound Semiconductors and their Heterostructures

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9624029 Weinstein The program investigates the effect of high hydrostatic pressure on the energy and competition of shallow (hydrogenic) and deep impurity states in III-V semiconductors and heterostructures, as well as on the possible occurrence and properties of stable excitonic states in these systems. The work will involve far infrared (FIR) magneto-spectroscopy and near infrared/visible optical experiments carried out using a unique diamondanvil apparatus that achieves in-situ tuning of pressure, temperature and magnetic field over the ranges 0150 kbar, 2300K and 0-17T. The approach will permit direct comparison of spectroscopic results recorded over a wide range of energies from the FIR to the visible on the same samples under the same conditions, which has not heretofore been possible. Such studies should yield (1) a much clearer picture of the competition between shallow and deep (both stable and metastable) impurity states in semiconductors for many different substitutional species, (2) should help establish the carrier density dependence of many-body effects in doped aluminumgallium arsenide/gallium-arsenide quantum well structures, and (3) should enable the exploration of conditions and properties for possible stable excitonic ground states in indium-arsenide/aluminium- gallium-antimony systems. %%% The program investigates the effect of high hydrostatic pressure on the energy and competition of shallow (hydrogenic) and deep impurity states in III-V semiconductors and hererostructures, as well as on the possible occurrence and properties of stable excitonic states in these systems. The work will involve far infrared (FIR) magneto- spectroscopy and near infrared/visible optical experiments carried out using a unique diamond-anvil apparatus that achieves in-situ tuning of pressure, temperature and magneti c field over the ranges 0- 150 kbar, 2-300K and 0-17T. The approach will permit direct comparison of spectroscopic results recorded over a wide range of energies from te far-infra-red to the visible. The experiments will be conducted on the same samples under the same conditions, which has not heretofore been possible. Such studies should yield: (1) a much clearer picture of the competition between shallow and deep (both stable and metastable) impurity states in semiconductors for many different substitutional species, (2) should help establish the carrier density dependence of many-body effects in doped aluminum- gallium-arsenide quantum well structures, and (3) should enable the exploration of conditions and properties for possible stable excitionic ground states in indium-arsenide/aluminium-gallium- antimony systems.***