Crystalline (Al$_{1-x}$B$_{x})$PSi$_{3}$ and~(Al$_{1-x}$B$_{x})$AsSi$_{3}$ tetrahedral phases via reaction of Al(BH$_{4})_{3}$ and M(SiH$_{3})_{3}$ (M$=$P, As)

Crystalline (Al$_{1-x}$B$_{x})$PSi$_{3}$ alloys ($x =$ 0.04-0.06) are grown lattice-matched on Si(100) by reactions of P(SiH3)3 and Al(BH4)3 using low-pressure CVD. The materials have been characterized by ellipsometry, XRD, XTEM, EELS and EDS, indicating the formation of single-phase monocrystalline layers with tetrahedral structures based on AlPSi$_{3}$. The latter comprises interlinked AlPSi$_{3}$ tetrahedra in which Al-P pairs are isolated within a Si matrix. Raman scattering of Al$_{1-x}$B$_{x}$PSi$_{3}$ films support the presence of substitutional B in place of Al and provides evidence that B is bonded to P. The substitution of B atoms is desirable for promoting lattice matching, as required for Si-based solar cell designs. Analogous reactions of As(SiH3)3 with Al(BH4)3 produce (Al$_{1-x}$B$_{x})$AsSi$_{3}$ in which the B incorporation is limited to doping concentrations at 10$^{20}$ cm$^{-3}$. In both cases the Al(BH4)3 efficiently delivers Al to create crystalline group IV-III-V materials comprising light, earth abundant elements with possible application in photovoltaics and light element refractory solids.