MOVPE growth of BxGa1-xAs, BxGa1-x-yInyAs, and BxAl1-xAs alloys on (001) GaAs

We have studied BxAl1-xAs. BxGa1-xAs, and BxGa1-x-yInxAs single layers and highly strained quantum-well structures grown by low-pressure metal-organic vapour-phase epitaxy. The epitaxial layers were grown oil (00 1) GaAs substrates with various misorientations using the precursors triethylboron. trimethylaluminium. trimethylgallium. trimethylindium. and arsine. The boron and indium compositions of the alloys were varied from 0less than or equal toxless than or equal to0.04 and 0less than or equal toyless than or equal to0.35, respectively. The influence of the growth conditions on structural quality. boron incorporation, interface quality. and optical properties Of bulk-like and quantum-well Structures is discussed. The growth modes of BxAl1-xAs and BxGa1-xAs were similar and the boron distribution coefficient,, were strongly affected by the growth temperature and the misorientation Of the Substrates. We observe a small influence of the boron concentration oil the band gap energies. In the case of BxGa1-xAs. only a small band gap shift with a bowing, parameter of 1.7 eV. and all enhancement of the stress-induced splitting between heavy and light hole valence bands kith increasing boron concentrations were found by photoluminescence and spectroscopic ellipsometry. (C) 2002 Elsevier Science B.V. All rights reserved.