The laser scanned photodiode: Theoretical and electrical models of the image sensor

Fernandes, M.; Vieira, M.; Martins, Rodrigo

doi:10.1016/j.jnoncrysol.2006.01.077

Cited by 5 publications

(2 citation statements)

References 3 publications

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“…This has been an important topic of research in the field of sensing applications. [1][2][3] Work on characterization and modeling of image sensor electrical behavior 4 led the way to the development of multilayer structures of interest for image and color sensor application: p-i-n structures for pattern detection of B/W images through the LSP (Laser Scanned Photodiode) technique; 5 and tandem structures for additional light wavelength discrimination. 6 7 Light filtering properties, namely light wavelength discrimination, depend on the structure of the sensor, mainly carbon doping, thickness of each pin cell absorbing layer, and the selected sequence of the cells in the multilayer structure.…”

Section: Introductionmentioning

confidence: 99%

Photocurrent and Spectral Response Analysis of a-SiC:H Pinip and Pinpin Photodiodes

Fantoni¹,

Vieira²,

Vygranenko³

et al. 2009

J. Nanosci. Nanotech.

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We present in this paper results about the analysis of photocurrent and spectral response in a-SiC:H/a-Si:H pinpin and pinip structures. Our experiments and analysis reveal the photocurrent profile to have a strong nonlinear dependence on the externally applied bias and on the light absorption profile, i.e., on the incident light wavelength and intensity. Our interpretation points out the cause of such effect to a self biasing of the junctions under certain unbalanced light generation of carriers and to an asymmetric reaction of the internal electric fields to the externally imposed bias. The possibility to relate such a behavior to the light intensity and wavelength indicates realistic hypothesis of using these structures and this effect for color recognition sensors. We present results about the experimental characterization of the structures and numerical simulations obtained with the program ASCA. Considerations about electrical field profiles and inversion layers will be taken into account to explain the optical and voltage bias dependence of the spectral response. Our results show that in both structures the application of an external electrical bias (forward or reverse) mainly influences the field distribution within the less photo excited sub-cell.

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Section: Introductionmentioning

confidence: 99%

Photocurrent and Spectral Response Analysis of a-SiC:H Pinip and Pinpin Photodiodes

Fantoni¹,

Vieira²,

Vygranenko³

et al. 2009

J. Nanosci. Nanotech.

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“…The results here presented have been obtained under standard DC regime and through the application of the Laser Scanner Photodiode (LSP) technique [6] (AC regime of the optical bias) which lead to a complete three color detection of the incoming light. The color detection is achieved by photocurrent measurement under three different values of the externally applied bias.…”

Section: Introductionmentioning

confidence: 99%

Fine Tuning of the Spectral Sensitivity in a-SiC:H Stacked p-i'i-n Graded Cells

Fantoni

Fernandes²,

Louro

et al. 2009

MRS Proc.

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It is presented in this work a p(a-SiC:H)/i(a-SiC:H)/i((a-Si:H)/ n(a-Si:H) single junction for application in color sensing domain produced with the PECVD technique. The interest of this device resides in its simplicity of realization and utilization, as it takes advantage from the well known properties of the a-Si:H p-i-n junctions together with the possibility of color filtering by tailoring the optical gap of a-Si:H with the introduction of a small percentage of Carbon. The thicknesses of the i(200 nm) and i (1000 nm) layers are optimized for light absorption in the blue and red ranges, respectively. Measurements of the spectral response under forward and reverse polarization show a dependence of the wavelength of the maximum absorption on the intensity of the applied bias. A comparison of the photocurrent reading with and without a 650 nm background DC optical bias permits a complete separation of blue and red color under reverse and forward applied bias, respectively. The application of the LSP technique (AC regime of the optical bias) permits a complete RGB reading of the incoming light. Simulation results obtained with the program ASCA will support and explain the measurements about spectral response and photocurrent reading under DC and AC regimes.

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Analysis and simulation of a‐Si:H/a‐SiC:H PINIP structures for color image detection

Fantoni¹,

Fernandes²,

Vygranenko³

et al. 2008

Physica Status Solidi (a)

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It is presented in this paper a study on the photo‐electronic properties of multilayer a‐Si:H/a‐SiC:H p–i–n–i–p structures. This study is aimed to give an insight into the internal electrical characteristics of such a structure in thermal equilibrium, under applied bias and under different illumination condition. Taking advantage of this insight it is possible to establish a relation among the electrical behavior of the structure, the structure geometry (i.e. thickness of the light absorbing intrinsic layers and of the internal n‐layer) and the composition of the layers (i.e. optical bandgap controlled through percentage of carbon dilution in the a‐Si1–x Cx:H layers). Showing an optical gain for low incident light power con‐ trollable by means of externally applied bias or structure composition, these structures are quite attractive for photo‐sensing device applications, like color sensors and large area color image detector. An analysis based on numerical ASCA simulations is presented for describing the behavior of different configurations of the device and compared with experimental measurements (spectral response and current–voltage characteristic). (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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The laser scanned photodiode: Theoretical and electrical models of the image sensor

Cited by 5 publications

References 3 publications

Photocurrent and Spectral Response Analysis of a-SiC:H Pinip and Pinpin Photodiodes

Photocurrent and Spectral Response Analysis of a-SiC:H Pinip and Pinpin Photodiodes

Fine Tuning of the Spectral Sensitivity in a-SiC:H Stacked p-i'i-n Graded Cells

Analysis and simulation of a‐Si:H/a‐SiC:H PINIP structures for color image detection

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