Dr. Kai Wang Profile

Dr. Kai Wang

Assistant Professor at SYSU CMU Joint Institute of Engineering

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Publications (17)

Proceedings Article | 4 April 2016 Paper

Design, optimization and evaluation of a “smart” pixel sensor array for low-dose digital radiography

Kai Wang, Xinghui Liu, Hai Ou, Jun Chen

Proceedings Volume 9783, 978362 (2016) https://doi.org/10.1117/12.2216780

KEYWORDS: Radiography, Signal to noise ratio, Amorphous silicon, Transistors, X-ray detectors, X-rays, Photons, Photomasks, X-ray imaging, Image sensors

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Proceedings Article | 10 August 2015 Paper

Evaluation of a single-pixel one-transistor active pixel sensor for fingerprint imaging

Man Xu, Hai Ou, Jun Chen, Kai Wang

Proceedings Volume 9620, 96200A (2015) https://doi.org/10.1117/12.2193336

KEYWORDS: Sensors, Image sensors, Optical sensors, Amplifiers, Active sensors, Switches, Capacitors, Field programmable gate arrays, LCDs, Liquid crystals

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Proceedings Article | 5 August 2015 Paper

Evaluation of a single-pixel one-transistor active pixel sensor for low-dose indirect-conversion X-ray imaging

Xinghui Liu, Hai Ou, Jun Chen, Kai Wang

Proceedings Volume 9622, 962208 (2015) https://doi.org/10.1117/12.2190775

KEYWORDS: Sensors, X-ray imaging, Active sensors, Light emitting diodes, Amplifiers, X-rays, Clocks, Field programmable gate arrays, Amorphous silicon, Electrodes

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Proceedings Article | 9 March 2012 Paper

Performance of a prototype 32x32 pixel indirect x-ray imager based on a lateral selenium passive pixel sensor

Rasoul Keshavarzi, Kai Wang, Mohammad Yazdandoost, Kyung-Wook Shin, Feng Chen, Shaikh Hasibul Majid, Shiva Abbaszadeh, Karim Karim

Proceedings Volume 8313, 83135O (2012) https://doi.org/10.1117/12.912286

KEYWORDS: Sensors, Selenium, X-rays, Field programmable gate arrays, X-ray imaging, X-ray detectors, Prototyping, Signal detection, Image quality, Imaging arrays

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Proceedings Article | 9 March 2012 Paper

Novel silicon x-ray detector with TFT readout

Kyung-Wook Shin, Kai Wang, Nicholas Allec, Yuan Fang, Karim Karim

Proceedings Volume 8313, 83135R (2012) https://doi.org/10.1117/12.911359

KEYWORDS: Sensors, Silicon, X-rays, X-ray detectors, Crystallography, Proteins, Interference (communication), Silicon films, Capacitance, Crystals

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Proceedings Article | 3 March 2012 Paper

Characterization of gated selenium photo detector

Shaikh Hasibul Majid, Kai Wang, Nicholas Allec, Umar Shafique, Karim Karim

Proceedings Volume 8313, 83135U (2012) https://doi.org/10.1117/12.912250

KEYWORDS: Sensors, Selenium, X-rays, Electrodes, Photodetectors, Photoresistors, X-ray detectors, X-ray imaging, Electric field sensors, Blue light emitting diodes

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Proceedings Article | 17 March 2011 Paper

Photon quantum shot noise limited array in amorphous silicon technology for protein crystallography applications

Mohammad Yazdandoost, K. Wang, Karim Karim

Proceedings Volume 7961, 79614O (2011) https://doi.org/10.1117/12.878118

KEYWORDS: Proteins, Crystallography, Amorphous silicon, Photonic crystals, Sensors, X-rays, CMOS technology, X-ray detectors, Signal detection, Oscillators

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An array of ring voltage controlled oscillators (RVCO) aiming for photon quantum shot noise limited applications such as protein crystallography is presented. The pixilated array consists of 24 by 21 RVCO pixels. RVCO pixel converts x-ray generated input charge into an output oscillating frequency signal. This architecture can be used in both direct and indirect detection schemes. In this paper the direct detection using a layer of amorphous selenium (a-Se) coupled with the RVCO array is proposed. Theoretical and Experimental results for an in-house fabricated array of RVCOs in amorphous silicon (a-Si) technology are presented. All different requirements for protein crystallography application are listed in this paper and also the way this array addresses each of these requirements is discussed in details in this paper. The off-panel readout circuitry, designed and implemented in-house, is given in this paper. The off-panel readout circuits play an important role in the imaging applications using frequency based pixels. They have to be optimized in order to reduce the fixed pattern noise and fringing effects in an imaging array containing many such RVCO pixels. Since the frequency of oscillation of each of these pixels is in the range of 100 KHz, there is no antenna effect in the array. Antenna effect becomes an important issue in other technologies such as poly silicon (poly-Si) and CMOS technologies due to higher frequency of oscillation ranges (more than 100 MHz). Noise estimations, stability simulations and measurements for some randomly selected pixels in the array for the fabricated RVCO array are presented. The reported architecture is particularly promising for large area photon quantum shot noise applications, specifically protein crystallography. However, this architecture can be used for low dose fluoroscopy, dental computed tomography (CT) and other large area imaging applications limited by input referred electronic noise due to its very low input referred electronic noise, high sensitivity and ease of fabrication in low cost a-Si technology.

Proceedings Article | 17 March 2011 Paper

Study of gain phenomenon in lateral metal-semiconductor-metal detectors for indirect conversion medical imaging

Shiva Abbaszadeh, Nicholas Allec, Kai Wang, Feng Chen, Karim Karim

Proceedings Volume 7961, 79614P (2011) https://doi.org/10.1117/12.877860

KEYWORDS: Selenium, Sensors, External quantum efficiency, Photons, Electrodes, Medical imaging, Quantum efficiency, Measurement devices, Photoresistors, Ionization

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Proceedings Article | 17 March 2011 Paper

Integration of an amorphous silicon passive pixel sensor array with a lateral amorphous selenium detector for large area indirect conversion x-ray imaging applications

Kai Wang, Mohammad Yazdandoost, Rasoul Keshavarzi, Kyung-Wook Shin, Christos Hristovski, Shiva Abbaszadeh, Feng Chen, Shaikh Hasibul Majid, Karim Karim

Proceedings Volume 7961, 79610V (2011) https://doi.org/10.1117/12.877592

KEYWORDS: Sensors, X-ray imaging, Amorphous silicon, Selenium, Blue light emitting diodes, Thin films, Capacitors, Photodetectors, Cesium, Electrodes

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Proceedings Article | 17 March 2011 Paper

Characterization and comparison of lateral amorphous semiconductors with embedded Frisch grid detectors on 0.18um CMOS processed substrate for medical imaging applications

Christos Hristovski, Amir Goldan, Shaikh Hasibul Majid, Kai Wang, Umar Shafique, Karim Karim

Proceedings Volume 7961, 79610Q (2011) https://doi.org/10.1117/12.877708

KEYWORDS: Sensors, Electrodes, External quantum efficiency, Amorphous semiconductors, CMOS sensors, Metals, Capacitance, Photoresistors, Photodetectors, Medical imaging applications

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Proceedings Article | 23 March 2010 Paper

Silicon nanowire metal-semiconductor-metal photodetectors

Michael Adachi, Kai Wang, Feng Chen, Karim Karim

Proceedings Volume 7622, 76224M (2010) https://doi.org/10.1117/12.845503

KEYWORDS: Photodetectors, Silicon, Electrodes, Aluminum, Amorphous silicon, Time metrology, Nanolithography, Blue light emitting diodes, Crystals, Nanowires

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Proceedings Article | 23 March 2010 Paper

Cadmium zinc telluride detector for low photon energy applications

Kyung-Wook Shin, Kai Wang, Alla Reznik, Karim Karim

Proceedings Volume 7622, 76223Z (2010) https://doi.org/10.1117/12.844047

KEYWORDS: X-rays, Sensors, Mammography, Photodetectors, X-ray imaging, Light emitting diodes, Cadmium, Zinc, Medical imaging, Single photon emission computed tomography

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Proceedings Article | 23 March 2010 Paper

Amorphous silicon p-i-n photodetector with Frisch grid for high-speed medical imaging

Nicholas Allec, Amir Goldan, Kai Wang, Feng Chen, Karim Karim

Proceedings Volume 7622, 76223X (2010) https://doi.org/10.1117/12.844025

KEYWORDS: Electrodes, Photodetectors, Sensors, Photons, Photoresistors, Photodiodes, Amorphous silicon, Electrons, Lithography, Absorption

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Proceedings Article | 23 March 2010 Paper

Amorphous selenium lateral Frisch photodetector and photomultiplier for high performance medical x-ray and gamma-ray imaging applications

A. Goldan, K. Wang, F. Chen, K. Karim

Proceedings Volume 7622, 76223R (2010) https://doi.org/10.1117/12.844809

KEYWORDS: Photodetectors, Electrodes, Selenium, Sensors, Gamma ray imaging, Photomultipliers, Crystals, X-ray imaging, X-ray detectors, Signal to noise ratio

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Proceedings Article | 19 March 2010 Paper

Lateral amorphous selenium metal-semiconductor-metal photodetector for large-area high-speed indirect-conversion medical imaging applications

Kai Wang, Feng Chen, Kyung-Wook Shin, Nicholas Allec, Karim Karim

Proceedings Volume 7622, 762217 (2010) https://doi.org/10.1117/12.843980

KEYWORDS: Sensors, Photodetectors, X-ray imaging, Selenium, X-rays, X-ray detectors, Electrodes, Electric field sensors, Sodium, Medical imaging applications

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Proceedings Article | 17 September 2009 Paper

Design and modeling of a lateral a-Se MSM photoconductor as indirect conversion X-ray imager

Kai Wang, Feng Chen, George Belev, Safa Kasap, Karim Karim

Proceedings Volume 7449, 74491W (2009) https://doi.org/10.1117/12.829299

KEYWORDS: Photodetectors, Photoresistors, X-ray imaging, External quantum efficiency, Sensors, Electrodes, Scintillators, Selenium, Amorphous silicon, Quantum efficiency

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Proceedings Article | 22 August 2009 Paper

Fabrication and characterization of cerium oxide thin films for ultraviolet sensing applications

Kai Wang, Alla Reznik, Karim Karim

Proceedings Volume 7425, 74250U (2009) https://doi.org/10.1117/12.827418

KEYWORDS: Cerium, Ions, Oxides, Ultraviolet radiation, Oxygen, Thin films, Refractive index, Ultraviolet detectors, Absorption, Ion beams

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Showing 5 of 17 publications

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