Numerical simulation on the effect of the thickness of the absorbing layer on the spectral response characteristics for GaAs-based blocked impurity band (BIB) terahertz detectors

To investigate the transient electromagnetic method of response characteristics in the tunnel geological prediction, the finite element numerical simulation of unfavorable geological body of different location, different resistivity sizes, different shapes, and different volume size were carried out by ANSYS finite element software. The results show that secondary electromagnetic field of different location of unfavorable geological body have same decay rate, when detection distance from 30m to 70m, transient electromagnetic responses are strongest, followed distance from 10m to 30m and from 70m to 90m. The shape, volume and resistivity of unfavorable geological body have strong influence on transient electromagnetic response, unfavorable geological body more sleek, the greater the volume and the smaller the resistivity of unfavorable geological body, the secondary electromagnetic field decay slower.

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Spectral response characteristics of concave grating demultiplexer

10.1117/12.688388 ◽

2006 ◽

Author(s):

Fuyuan Guo ◽

Minghua Wang

Keyword(s):

Spectral Response ◽

Response Characteristics ◽

Concave Grating

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Two-dimensional a-Si:H/a-SiC:H n-i-p sensor array with ITO/a-SiNx antireflection coating

MRS Proceedings ◽

10.1557/proc-862-a9.4 ◽

2005 ◽

Vol 862 ◽

Cited By ~ 2

Author(s):

Yu. Vygranenko ◽

J. H. Chang ◽

A. Nathan

Keyword(s):

Reverse Bias ◽

Spectral Response ◽

Charge Trapping ◽

Optical Excitation ◽

Antireflection Coating ◽

Two Dimensional ◽

Device Structure ◽

Response Characteristics ◽

Photodiode Array

AbstractThis paper presents a two-dimensional a–Si:H/a-SiC:H n–i–p photodiode array with switching diode readout, developed specifically for fluorescence-based bio-assays. Both device structure and fabrication processing has enabled enhancement of the external quantum efficiency of the encapsulated device up to 80%, reduction of the photodiode leakage down to 10 pA/cm2 at -1V reverse bias, and increase of the rectification current ratio of the switching diodes up to 109. The critical fabrication issues associated with deposition of device-quality materials, tailoring of defects at the i–p interface, device patterning with dry etching, junction passivation, and contact formation will be discussed. Both sensing and switching diodes were characterized. While the observed dark current in the photodiodes at low reverse bias voltages is primarily due to carrier emission from deep states in the a–Si:H bulk, the leakage in the small switching diodes stems from peripheral defects along junction sidewalls. Optical losses in the photodiodes with ITO/a–SiNx:H antireflection coating were evaluated using numerical modeling, and the calculated transmission spectra correlated well with the spectral response characteristics. Measurements of the charge transfer time and output linearity demonstrated the efficiency of the single-switching diode readout configuration. The response of the array to optical excitation was also investigated. The observed long term retardation in the signal rise and decay at illumination levels less than 1010 photons/cm2-s can be associated with charge trapping in the undoped layer.

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