The large difference in interatomic spacing between GaN and InN is found to give rise to a solid phase miscibility gap. The temperature dependence of the binodal and spinodal lines in the Ga1−xInxN system was calculated using a modified valence-force-field model where the lattice is allowed to relax beyond the first nearest neighbor. The strain energy is found to decrease until approximately the sixth nearest neighbor, but this approximation is suitable only in the dilute limit. Assuming a symmetric, regular-solutionlike composition dependence of the enthalpy of mixing yields an interaction parameter of 5.98 kcal/mole. At a typical growth temperature of 800 °C, the solubility of In in GaN is calculated to be less than 6%. The miscibility gap is expected to represent a significant problem for the epitaxial growth of these alloys.

No abstract

Infrared photoluminescence (PL) from InSb, InAs, and InAs1−xSbx (x<0.3) epitaxial layers grown by atmospheric pressure organometallic vapor phase epitaxy has been investigated for the first time over an extended temperature range. The values of full width at half maximum of the PL peaks show that the epitaxial layer quality is comparable to that grown by molecular-beam epitaxy. The observed small peak shift with temperature for most InAs1−xSbx epilayers may be explained by wave-vector-nonconserving transitions involved in the PL emission. For comparison, PL spectra from InSb/InSb and InAs/InAs show that the wave-vector-conserving mechanism is responsible for the PL emission. The temperature dependence of the energy band gaps, Eg, in InSb and InAs is shown to follow Varshni’s equation Eg(T)=Eg0−αT2/ (T+β). The empirical constants are calculated to be Eg0=235 meV, α=0.270 meV/K, and β=106 K for InSb and Eg0=415 meV, α=0.276 meV/K, and β=83 K for InAs.

No abstract

No abstract