Sj. Joo et al., Visible photoluminescence at room temperature from a-Si : H films grown byultrahigh vacuum electron cyclotron resonance chemical vapor deposition, J KOR PHYS, 35, 1999, pp. S1025-S1028
Hydrogenated amorphous Si (a-Si:H) films were grown without external heatin
g by ultrahigh vacuum electron cyclotron resonance chemical vapor depositio
n (UHV-ECRCVD) and structural/optical properties were characterized. Visibl
e red photoluminescence (PL), centered around the wavelengths of similar to
700 nm, is obtained from the as-grown samples at room temperature. Strong
oscillation of PL spectra is observed in the films grown on oxidized Si sub
strates, which is believed to originate from Fabry-Perot interference effec
t. As-grown a-Si:H films do not contain Si nanocrystals, and a large amount
of (SiH2)(n)(polysilane) bonding is found. PL intensity depends on deposit
ion conditions, but it usually becomes stronger as the polysilane-content i
n the as-grown film increases. When the samples are annealed at 350 degrees
C, integrated PL intensity is quenched almost completely as the polysilane
content falls off abruptly. Based on these results, possible luminescence
mechanisms are discussed.