Materials Science and Engineering B,
Monday, March 9, 2015
Vertically-aligned nanostructured silicon ﬁlms are deposited at room temperature on p-type sili- con wafers and glass substrates by inductively-coupled, plasma-enhanced chemical vapor deposition (ICPCVD). The nanocrystalline phase is achieved by reducing pressure and increasing RF power. The crys- talline volume fraction (X c ) and the size of the nanocrystals increase with decreasing pressure at constant power. Columnar growth of nc-Si:H ﬁlms is observed by high resolution transmission electron microscopy (HRTEM) and scanning electron microscopy (SEM). The ﬁlms exhibit cauliﬂower-like structures with high porosity that leads to slow but uniform oxidation after exposure to air at room temperature. Films deposited at low pressures exhibit photoluminescence (PL) signals that may be deconvoluted into three distinct Gaussian components: 760–810, 920–935, and 990–1000 nm attributable to the quantum con- ﬁnement and interface defect states. Hydrogen dilution is manifested in signiﬁcant enhancement of the PL, but it has little effect on the nanocrystal size and X c .