Abstract
a-Si:H films were prepared by hot wire chemical vapor deposition. One group was deposited at a substrate temperature of Ts=250°C with varied hydrogen-dilution ratio, O<R<10; the other group was deposited with fixed R=3 but a varied Ts from 150 to 550°C. IR, Raman and PL spectra were studied. The Raman results indicate that there is a threshold value for the microstructure transition from a- to μc-Si. The threshold is found to be R ≈ 2 at Ts = 250°C and Ts ≈ 200°C at R=3. The IR absorption of Si-H at 640 cm-1 was used to calculate the hydrogen content, CH. CH decreased monotonically when either R or Ts increased. The Si-H stretching mode contains two peaks at 2000 and 2090 cm-1. The ratio of the integral absorption peaks I2090/(I2090+I2090) showed a sudden increase at the threshold of microcrystallinity. At the same threshold, the PL features also indicate a sudden change from a- to μc-Si., i.e. the low energy PL band becomes dominant and the PL total intensity decreases. We attribute the above IR and PL changes to the contribution of microcrystallinity, especially the c-Si gain-boundaries.
Original language | American English |
---|---|
Pages | 147-152 |
Number of pages | 6 |
DOIs | |
State | Published - 2002 |
Event | Amorphous and Heterogeneous Silicon Films 2002 - San Francisco, CA, United States Duration: 2 Apr 2002 → 5 Apr 2002 |
Conference
Conference | Amorphous and Heterogeneous Silicon Films 2002 |
---|---|
Country/Territory | United States |
City | San Francisco, CA |
Period | 2/04/02 → 5/04/02 |
NREL Publication Number
- NREL/CP-520-34494