Growth by Liquid-Phase Epitaxy and Characterization of Al_0.28Ga_0.72As_0.62P_0.38

Abstract

Al0.28Ga0.72As0.62P0.38 epitaxial layers were grown on GaAs0.61P0.39 substrates by liquid-phase epitaxy using a supercooling technique. The growth conditions and properties of the undoped AlGaAsP layers are described in detail. A fairly shiny surface and a flat AlGaAsP-GaAsP heterointerface was obtained in our study. The lattice mismatch normal to the wafer surface between the Al0.28Ga0.72As0.62P0.38 layer and GaAs0.61P0.39 substrate is ∼+0.27%. Low-electron-concentration undoped epitaxial layers can be grown from a Ga solution baked at a temperature of 900°C for 10 h or more and with a ∼6°C supersaturation temperature. We obtained the lowest electron concentrations of 1×1016 cm-3 measured by the capacitance-voltage method. By the photoluminescence measurements at various temperatures and excitation levels, the four recombination peaks observed are associated with the near-band-to-band, donor-to-valence-band, conduction-band-to-acceptor and donor-to-acceptor-pair transitions. The band gap of the Al0.28Ga0.72As0.62P0.38 is ∼2.016 eV (6150 Å). The binding energy of the donor and acceptor is 14 and 36 meV, respectively.

Band parameters for III–V compound semiconductors and their alloys

“…AlGaAsP has been grown on commercially available GaAs 0.61 P 0.39 substrates. [711][712][713] It can be considered as a combination of GaAsP and AlAsP alloys with phosphorus fractions similar to the substrate. A careful investigation of the pump intensity dependence of the PL peaks revealed both impurity and band-to-band transitions.…”