Highly photosensitive helium diluted amorphous silicon 1.5 eV band gap: Role of pressure
- 1 July 1995
- journal article
- conference paper
- Published by AIP Publishing in Journal of Applied Physics
- Vol. 78 (1) , 581-583
- https://doi.org/10.1063/1.360575
Abstract
Highly photosensitive low band gap (≥1.5 eV) hydrogenated amorphous silicon (a‐Si:H) films have been developed by plasma enhanced chemical vapor deposition using helium dilution of the process gas, silane at substrate temperature 210 °C. Low band gap of a‐Si:H films is achieved by reducing bonded hydrogen content and hence by increasing compactness of the films. At the optical gap ∼1.5 eV, a‐Si:H film has high mobility lifetime product, ημτ (8×10−5 cm−2 V−1) and photosensitivity (≳7×104) values. The defect density of the material is as low as 7.8×1015 cm−3 eV−1 and hydrogen content is 4.54 at. %. Low band gap amorphous silicon germanium (a‐SiGe:H) films reported so far do not have such high ημτ and photosensitivity values at 1.5 eV optical gap. Thus, this low band gap a‐Si:H films can be used as intrinsic layer in the bottom cell of a multijunction solar cell replacing a‐SiGe:H alloy films.This publication has 13 references indexed in Scilit:
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