Time resolved photoluminescence of hydrogenated amorphous silicon carbon thin films deposited by HWCVD

Hydrogenated amorphous silicon carbon (a-SiC:H) alloys deposited by Hot Wire Chemical Vapor Deposition (HWCVD) technique have been extensively characterized by room temperature photoluminescence (PL) and time resolved photoluminescence (TRPL). The films were deposited under different sets of conditions of acetylene (C2H2) flow rate and hydrogen dilution. The temporal behavior of photoluminescence decay measured at peak emission energy exhibits a bi-exponential decay processes with lifetime of the order of a few nanoseconds. The variation in the process conditions leads to variations in the compositional and structural properties of the films, which affect the PL decay. The B-parameter which is the slope of the plot of absorption coefficient with photon energy has been determined for these films along with the carbon content. A systematic correlation between the carbon content and the decay time has been seen which is affected by an increase of hydrogen dilution or the C2H2 flow. (c) 2006 Elsevier B.V. All rights reserved.