NEAR-BAND-EDGE PHOTOLUMINESCENCE FROM PSEUDOMORPHIC TENSIALLY STRAINED SI0.985C0.015 ALLOY

Band edge related low temperature photoluminescence of a strained Si0. 985C0.015 bulk alloy layer grown by molecular beam epitaxy on a Si (10 0) substrate has been investigated. The high quality layer was grown t o a thickness of 1500 Angstrom and was found to be pseudomorphic and t ensially strained. We report two dominant features, a well-resolved ba nd-edge luminescence consisting of a no-phonon and a transverse optica l phonon replica, and an intense deep level luminescence peak around 0 .778 eV. We band edge feature is attributed to a no-phonon free excito nic recombination in the binary alloy. We also observe a red shift of the energy gap of Si0.985C0.015 alloy with respect to Si, contrary to what is predicted according to the bulk alloy effect.