论文信息 - Optimization of hydrogenated amorphous silicon p–i–n solar cells with two-step i layers guided by real-time spectroscopic ellipsometry

Optimization of hydrogenated amorphous silicon p–i–n solar cells with two-step i layers guided by real-time spectroscopic ellipsometry

Hydrogenated amorphous silicon (a-Si:H) p–i–n solar cell performance has been optimized using a two-step i-layer growth process. This effort has been guided by real-time spectroscopic ellipsometry (RTSE) studies of the nucleation and growth of a-Si:H films by plasma-enhanced chemical vapor deposition at 200 °C using a variable H2-dilution gas flow ratio R=[H2]/[SiH4]. RTSE studies during film growth with R>15 reveal a transition from the amorphous to microcrystalline (a→μc) phase at a critical thickness that decreases with increasing R. From such results, the optimum two-step process was designed such that the initial stage of the i layer (∼200 A) is deposited at much higher R than the bulk to ensure that the film remains within the amorphous side of the a→μc phase boundary, yet as close as possible to this boundary at low i-layer thicknesses.

[1] N. Hata,et al. Steady state defect density and annealing kinetics of light-induced defects in a-Si:H deposited from 'new' deposition techniques , 1996 .

[2] H2-Dilution vs. Buffer Layers for Increased Voc , 1996 .

[3] R. Collins,et al. Real time spectroscopic ellipsometry study of hydrogenated amorphous silicon p‐i‐n solar cells: Characterization of microstructural evolution and optical gaps , 1995 .

[4] G. H. Bauer,et al. Bandgap engineering of amorphous semiconductors for solar cell applications , 1995 .

[5] W. F. V. D. Weg,et al. Defect and Band Gap Engineering of Amorphous Silicon Solar Cells , 1993 .

[6] Collins,et al. Thin-film coalescence in hydrogenated amorphous silicon probed by spectroscopic ellipsometry with millisecond-scale resolution. , 1992, Physical review letters.

[7] Robert W. Collins,et al. Automatic rotating element ellipsometers: Calibration, operation, and real‐time applications , 1990 .

[8] Stanford R. Ovshinsky,et al. Band‐gap profiling for improving the efficiency of amorphous silicon alloy solar cells , 1989 .

[9] A. Matsuda,et al. Guiding principle for preparing highly photosensitive Si-based amorphous alloys , 1987 .

[10] A. Catalano,et al. Amorphous silicon p-i-n solar cells with graded interface , 1986 .

[11] Makoto Konagai,et al. A novel structure, high conversion efficiency p-SiC/graded p-SiC/i-Si/n-Si/metal substrate-type amorphous silicon solar cell , 1984 .