Molecular beam epitaxial growth of high structural perfection CdTe on Si using a (Ca,Ba)F2 buffer layer

Epitaxial CdTe has been grown onto Si(111) by molecular beam epitaxy (MBE) with the aid of a graded CaF2-BaF2 buffer layer. The buffer of ∼2000 Å thickness was used to overcome the large lattice mismatch of 19%; it was deposited by MBE in a separate system. The ∼10-μm-thick CdTe films exhibited specular surfaces and showed strong photoluminescence. The width of the near-band-edge peak at 77 K was 12 meV, and (333) x-ray lines were about 80 arc s wide. These values indicate a high structural quality, comparable to well-known CdTe layers on alternate substrates like GaAs, InSb, or sapphire.