ISSN:
1089-7550
Source:
AIP Digital Archive
Topics:
Physics
Notes:
Spectroscopic ellipsometry measurements have been used as a probe to provide information on the structure of a hydrogenated amorphous silicon based n-i two-layer system. The n-i structure is prepared under the same conditions as an a-Si:H p-i-n cell with a thin (∼150 A(ring)) n layer deposited in a glow discharge from a mixture of SiF4, SiH4, H2, and PH3 on top of intrinsic a-Si:H. An effective medium approximation and a linear regression analysis have been used to determine the bulk microstructure of the thick (0.3 μm) n layer on quartz as a mixture of volume fractions of a-Si (0.74±0.01), c-Si (0.09±0.02), and void (0.17±0.03). When applied to the thin n layer in the solar-cell configuration, however, the corresponding analysis shows evidence of a 100-A(ring) overlayer of very low density a-Si, not observed on the thicker n-type material, which dominates the dielectric properties of the thin layer. These results are suggestive of nucleation and growth surface microstructure on the 150-A(ring) n layer and lead to the conclusion that, in the fabrication of high-performance a-Si:H based devices using thin layers, such structure must be minimized.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.335361
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