X-ray diffraction and excitation photoluminescence analysis of ordered GaInP

Abstract

X-ray diffraction is shown to provide a direct, quantitative, structural measurement of the degree of spontaneous ordering in GaInP. In this paper we combine x-ray diffraction and excitation photoluminescence analyses of CuPt-ordered GaInP, and comparing the results to theoretical predictions for the dependence of the band structure on order parameter, determine the values of the band-gap reduction and crystal-field splitting parameters for the perfectly ordered alloy. ͓S0163-1829͑98͒06447-9͔

Effects of the orientational superlattice on the electronic and vibrational properties of CuPt ordered GaInP alloys

“…Similarly, M1639d-6°B is shown to be a single variant ordered sample with x Ga D 0.523 and Á D 0.50 š 0.02. 16 The second pair, K518-0°and K782-6°B, were grown under identical conditions, except one was on an exact (001) and the other on a 6°B tilt GaAs substrate. The Ga compositions were measured by x-ray spectrometry to be x D 0.511 and 0.512, respectively.…”

Reciprocal space mapping of ordered domains in InxGa1−xP

“…1,2 Ordering is an important phenomenon for device applications as it influences the fundamental properties of a semiconductor alloy, such as the bandgap, surface morphology and the free carrier mobility. In the In 0.5 Ga 0.5 P system studied here, perfect ordering is predicted to reduce the bandgap by almost 500 meV, 3,4 while experiments have reported reductions up to 190 meV. 5,6 This is of particular importance for the solar cells under investigation here, as a decrease in bandgap changes efficiency.…”

“…High resolution x-ray diffraction techniques have been less extensively employed, although recently the order parameter has been determined using x-ray diffraction. 4 The size of ordered domains (L) has also been estimated from the width of the diffraction peak (∆q), using the Scherrer equation, L ≅ 1/ |∆q|, where q = (S-S 0 )/λ is the scattering vector. 8 However, mosaic broadening may also contribute to the width of the diffraction peak in rocking scans (ω scans), although for nearly lattice-matched InGaP layers on GaAs the contribution is expected to be small.…”

1.6/1.1eV metamorphic GaInP/GaInAs solar cells grown by MOVPE on Ge

“…The intensity of that peak compared to a nominal zincblende reflection of the GaInP layer can be used to calculate the order parameter directly, without relying on theoretical effects on the band gap [17]. Fig.…”