Structural changes in a-Si:H films deposited on the edge of crystallinity

Conference · Thu Jul 01 04:00:00 EDT 1999

OSTI ID:20107913

Mahan, A H; Yang, J; Guha, S; Williamson, D L

Using infrared, H evolution and x-ray diffraction (XRD), the structure of high H dilution, glow discharge deposited a-Si:H films on the edge of crystallinity is examined. From the Si-H wag mode peak frequency and the XRD results, the authors postulate the existence of very small Si crystallites contained within the as-grown amorphous matrix, with the vast majority of the bonded H located on these crystallite surfaces. Upon annealing at ramp rates of 8--15 C/min, a H evolution peak at {approximately} 400 C appears, and film crystallization is observed at temperatures as low as 500 C, both of which are far below those observed for a-Si:H films grown without H dilution using similar rates. While the crystallite volume fraction is too small to be detected by XRD in the as-grown films, these crystallites enable the crystallization of the remainder of the amorphous matrix upon moderate annealing, thus explaining the existence of the low temperature H evolution peak.

• Research Organization: National Renewable Energy Lab., Golden, CO (US)
• Sponsoring Organization: US Department of Energy
• DOE Contract Number: AC36-99GO10337
• OSTI ID: 20107913
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
36 MATERIALS SCIENCE
AMORPHOUS STATE
CHEMICAL BONDS
CRYSTALLIZATION
HYDROGEN ADDITIONS
MICROSTRUCTURE
SILICON
SOLAR CELLS