Misfit strain, relaxation, and band-gap shift in GaxIn1−xP/InP epitaxial layers

Abstract

A detailed investigation of the structural and optoelectronic properties of thick GaInP epilayers on sulfur-doped InP substrates is reported. Significant variations of the optical absorption and photoluminescence transition energies from light- and heavy-hole states are observed as a function of the epilayer composition as well as of the degree of relaxation of the misfit strain. High-resolution x-ray measurements were used to determine the Ga concentrations and the strains and indicate significant anisotropic relaxation in several films. Even small relaxations result in a significant increase in the optical linewidths and a rapid drop in the transition intensities. A model with no free parameters based on the strain Hamiltonian of Pikus and Bir provides excellent agreement with the transition energies and serves to identify unambiguously the transitions observed in the optical spectra. Within this model, isotropic in-plane relaxation produces a shift of both light- and heavy-hole energies whereas anisotropic in-plane relaxation contributes only negligibly.

Self-consistent determination of the band offsets inInAsxP1−x/Beaudoin1, Bensaada2, Leonelli3 et al. 1996Phys. Rev. BSelf Cite544210View full textAdd to dashboardCite

“…Symmetric ͑004͒ rocking curves were carried out on a Philips high-resolution five-crystal diffractometer, using the Cu K␣ 1 radiation with the monochromator aligned in its Ge͑220͒ settings. 22 These rocking curves are then analyzed using a computer simulation program developed by Fewster based on the dynamical diffraction theory. 23 Figure 1 shows a typical 24 HRXRD curve along with the fit ͑bottom shifted line͒ for sample No.…”

Atomic Layer Epitaxial Growth of Gaas on Porous Silicon Substrate

“…In our case the values of the free hole density p calculated from PL data are 4.42 10 18 cm -3 for HTGaAsPSi and 6.05 10 17 cm -3 for LTGaAs-PSi. The results of Tabata [13] and Bensaada [14] show that the PL analyses can be used to measure strain. The half-width of the PL peak increases with the misfit dislocations.…”

Modeling of Strain Induced by Compositional Variation in Wafer-Shaped Bulk Mixed Crystals

“…Consequently, in-plane strain can be assumed in the crystal. Although well known epilayer strain models [7][8][9][10] have been used to solve the inplane strain issues in epilayers, they cannot be applied to evaluate the strain in bulk mixed crystals, because strain in epilayers is induced by the abrupt change in lattice constant, which is not the case in bulk mixed crystals. However, the proposed strain model can be applied to investigate the strain in epilayers as well as in bulk mixed crystals.…”