The operational principle of a new amorphous silicon based p-i-i-n color detector

Abstract

The operational principle of a new type p-i-i-n color sensor is described with the aid of numerical modeling. The modeling results account for the color detection mechanism recently presented that this kind of structure exhibits [T. Neidlinger, M. B. Schubert, G. Schmid, and H. Brummack, in Amorphous Silicon Technology—1996, edited by E. A. Schiff et al. (Materials Research Society, Pittsburgh, 1996), p. 147]. By band gap engineering the experimental red response is maximized at larger reverse bias voltage whereas the green response has its maximum at low reverse bias voltage. The numerical modeling qualitatively reproduces the characteristic shape of the steady-state current-voltage curves at different illumination wavelengths. At low and at high reverse bias voltages the influence of the internal variables and parameters is identified and leads to the experimentally observed response. The potential profile of the p-i-i-n structure is of crucial importance to the color detection mechanism. At larger wavelengths the large potential drop across the two highly defective front layers assists recombination in the back part of the device, which thus leads to the drop in the red response at low reverse voltage. For the voltage-dependent shift in spectral sensitivity it is important that photogenerated carriers under green bias illumination are lost by recombination in the front part of the device.

Amorphous silicon based p–i–i–n photodetector detects 12 nm thin protein layers

“…To detect this shift, spectrally selective photodetectors are needed. Therefore we use amorphous Silicon (a-Si) based p-i-i-n diodes [2], which change their spectral sensitivity depending on the read-out voltage.…”

Preparation of nano-structured InGaAs thin film by molecular beam epitaxy

“…Nanocrystalline Si (nc-Si) and amorphous Si (a-Si) thin films are being successfully used in electronic devices, such as, photovoltaics , thin film transistors , flat-panel displays and image sensors [1,2,3]. Nanocrystalline InGaAs (nc-InGaAs) and amorphous InGaAs (a-InGaAs) are a candidate material for optoelectronic devices, such as sensors.…”

Characterization of nanocrystalline silicon carbide films

“…Due to its fine tunable electrical and optical properties by plasma parameters, hydrogenated amorphous silicon carbide films have attracted a great interest and have been used in many kinds of optoelectronic devices, such as solar cell windows layer, color sensors, and thin film light emitting and detecting devices [1][2][3][4][5]. Crystalline SiC compared to its amorphous counterpart has been considered to be a promising semiconductor material to operate at high temperature, high power, high frequency, and high radiation environment due to its good electrical and mechanical characteristics such as electron mobility (1000 cm 2 /V s), electron saturation velocity (2.0-2.7 · 10 7 cm/s), break electronic field (2-3 · 10 6 V/cm), high melting point and high thermal conductivity [6].…”