Band gap and mass renormalisation in GaIaP/AlGaInP quantum wells

We report magneto-luminescence studies of dense electron-hole plasmas in compressively strained GaInP/AlGaInP quantum wells. At carrier densities of order 10(13) cm(-2) many-body effects are investigated. The band gap is reduced by up to 36 meV, much less than expected from conventional random phase approximation calculations. However, much better agreement is obtained on comparison with recent density functional calculations which include the Hartree energy. The reduced mass is found to increase by up to 40% over values from low-excitation measurements. Comparison with other work suggests that the mass renormalisation is substantial in materials with wide band gaps. (C) 1998 Elsevier Science B.V. All rights reserved

The effect of substrate misorientation on atomic ordering in Ga0.52In0.48P epilayers grown on GaAs(001) substrates by gas-source MBE

The ternary III-V semiconductor Ga0.52In0.48P grown on GaAs substrate has been studied for visible wavelength light sources for information processing, laser printing and compact disk systems. In epilayers grown by MOCVD or Solid Source MBE, optical emission with reduced energy is known to originate from atomic ordering of the alloy and the degree of ordering of the group III elements has been found to be significantly influenced by the degree of substrate misorientation from (001). This paper reports a Transmission Electron Microscopy (TEM) study conducted on Ga0.52In0.48P epilayers grown on misoriented (001) GaAs substrates by Gas-Source Molecular Beam Epitaxy. For a growth temperature of 530 degrees C, substrate off-cut angles of 0 degrees, 7 degrees, 10 degrees and 15 degrees towards [111]A were investigated. Selected Area Diffraction Patterns obtained, indicated that the antiphase domain size decreases with increasing off-cut. TEM results have been correlated with band gap measurements obtained from PL and PLE spectra. The band gaps of Ga(0.52)ln(0.48)P epilayers grown by GS-MBE were found to be larger than those of the same composition grown by MOCVD or Solid Source MBE. This indicates potential for laser devices of shorter wavelengths

The effect of substrate misorientation on atomic ordering in Ga0.52In0.48P epilayers grown on GaAs(001) substrates by gas-source MBE

The ternary III-V semiconductor Ga0.52In0.48P grown on GaAs substrate has been studied for visible wavelength light sources for information processing, laser printing and compact disk systems. In epilayers grown by MOCVD or Solid Source MBE, optical emission with reduced energy is known to originate from atomic ordering of the alloy and the degree of ordering of the group III elements has been found to be significantly influenced by the degree of substrate misorientation from (001). This paper reports a Transmission Electron Microscopy (TEM) study conducted on Ga0.52In0.48P epilayers grown on misoriented (001) GaAs substrates by Gas-Source Molecular Beam Epitaxy. For a growth temperature of 530 degrees C, substrate off-cut angles of 0 degrees, 7 degrees, 10 degrees and 15 degrees towards [111]A were investigated. Selected Area Diffraction Patterns obtained, indicated that the antiphase domain size decreases with increasing off-cut. TEM results have been correlated with band gap measurements obtained from PL and PLE spectra. The band gaps of Ga(0.52)ln(0.48)P epilayers grown by GS-MBE were found to be larger than those of the same composition grown by MOCVD or Solid Source MBE. This indicates potential for laser devices of shorter wavelengths

Magneto-optical studies of compressively strained GaInP/AlGaInP multiple quantum wells

A series of compressively strained G(0.44)In(0.56)P/(Al0.7Ga0.3)(0.52)In-0.48 P multiple quantum well structures have been studied in magnetic fields up to 45 T. Laudau levels from several excitomic transitions have been observed in reflectivity spectra, allowing an accurate determination of the carrier masses and excitonic binding energies. It is shown that while the observed masses are lower than those seen in unstained GaInP/AlGaInP for wide wells, as the width decreases the mass in the strained samples increases sharply