Resumo

RUBINELLI, F. A  e  DE GREEF, M. Spectral Responses Over Unity in µc-Si:H n-i-p Junctions. An. AFA [online]. 2016, vol.27, n.1, pp.24-29. ISSN 0327-358X.

Spectral responses (SR) above the unity in the blue region of the spectrum in µc-Si:H based p-i-n devices optimized for photovoltaic and optical sensor applications when are illuminated with a red bias light, known as Complementary Photo-gating Effect, have not yet been observed. Calibrating the input parameters of the computer code D-AMPS by matching experimental SR and current voltage (J-V) characteristics the necessary conditions to predict anomalous responses at blue wavelengths were explored. SR>1 requires the presence of a defective p/i interface with a density of defects. The probe beam in the blue region modulates the carrier concentration at the defective p/i interface and the front region of the intrinsic layer, strengthen and weakening the field inside the intrinsic layer and at the p-doped layer and p/i interface respectively. This redistribution reduces the recombination rate inside the intrinsic layer giving rise to a gain and the SR>1. The phenomenon is predicted for devices with p-layers with either a high mobility gap such as a-SiC:H or a low mobility gap such as µc-Si:H whenever Boron has not been efficiently incorporated. SR>1 are very sensitive to electrical parameters of the p/i interface such as mobility gap, thickness, density of defects, mobilities and capture cross sections of donor traps, etc, and to the Boron density in the p-layer. They also show a high sensitivity to the spectral content of the bias light.

Palavras-chave : Spectral Response; Solar Cells; Optical Detectors; Micro-crystalline Silicon.

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