Dr. Pok-Kai Liao Profile

Dr. Pok-Kai Liao

at Leonardo DRS

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Publications (9)

Proceedings Article | 26 May 2016 Paper

Infrared optical and electronic properties in low tellurium doped GaSb substrates for SLS FPA applications

K. Roodenko, P.-K. Liao, D. Lan, K. Clark, E. Fraser, K. Vargason, J.-M. Kuo, Y.-C. Kao, P. Pinsukanjana

Proceedings Volume 9854, 985415 (2016) https://doi.org/10.1117/12.2234694

KEYWORDS: Gallium antimonide, Absorption, Tellurium, Doping, Infrared radiation, Staring arrays, FT-IR spectroscopy, Epitaxy, Infrared lasers, Semiconducting wafers, Transmittance, Wafer-level optics

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Proceedings Article | 4 May 2010 Paper

High operating temperature MWIR detectors

M. Kinch, H. Schaake, R. Strong, P. Liao, M. Ohlson, J. Jacques, C.-F. Wan, D. Chandra, R. Burford, C. Schaake

Proceedings Volume 7660, 76602V (2010) https://doi.org/10.1117/12.850965

KEYWORDS: Diodes, Mercury cadmium telluride, Mid-IR, Doping, Staring arrays, Metals, Copper, Photodiodes, Diffusion, Semiconductors

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Proceedings Article | 23 January 2010 Paper

High operating temperature MWIR detectors

H. Schaake, M. Kinch, D. Chandra, P. K. Liao, D. Weirauch, C.-F. Wan, H. D. Shih

Proceedings Volume 7608, 76081O (2010) https://doi.org/10.1117/12.846254

KEYWORDS: Diodes, Arsenic, Sensors, Mercury cadmium telluride, Metals, Interfaces, Doping, Mercury, Readout integrated circuits, Liquid phase epitaxy

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Proceedings Article | 18 May 2006 Paper

SWIR to LWIR HDVIP HgCdTe detector array performance

A. D'Souza, M. Stapelbroek, L. Dawson, P. Ely, C. Yoneyama, J. Reekstin, M. Skokan, M. Kinch, P. Liao, M. Ohlson, P. Ronci, T. Teherani, H. Shih, J. Robinson

Proceedings Volume 6206, 62062H (2006) https://doi.org/10.1117/12.669071

KEYWORDS: Sensors, Long wavelength infrared, Readout integrated circuits, Short wave infrared radiation, Mercury cadmium telluride, Quantum efficiency, Detector arrays, Mid-IR, Staring arrays, Diodes

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DRS uses LPE-grown SWIR, MWIR and LWIR HgCdTe material to fabricate High-Density Vertically Integrated Photodiode (HDVIP) architecture detectors. 2.5 μm, 5.3 μm and 10.5 μm cutoff detectors have been fabricated into linear arrays as technology demonstrations targeting remote sensing programs. This paper presents 320 x 6 array configuration technology demonstrations' performance of HDVIP HgCdTe detectors and single detector noise data. The single detector data are acquired from within the 320 x 6 array. Within the arrays, the detector size is 40 μm x 50 μm. The MWIR detector array has a mean quantum efficiency of 89.2% with a standard deviation to mean ratio, σ/μ = 1.51%. The integration time for the focal plane array (FPA) measurements is 1.76 ms with a frame rate of 557.7 Hz. Operability values exceeding 99.5% have been obtained. The LWIR arrays measured at 60 K had high operability with only ~ 3% of the detectors having out of family response. Using the best detector select (BDS) feature in the read out integrated circuit (ROIC), a feature that picks out the best detector in every row of six detectors, a 320 x 1 array with 100% operability is obtained. For the 320 x 1 array constituted using the BDS feature, a 100% operable LWIR array with average NEI value of 1.94 x 10¹¹ ph/cm²/s at a flux of 7.0 x 10¹⁴ ph/cm²/s has been demonstrated. Noise was measured at 60 K and 50 mV reverse bias on a column of 320 diodes from a 320 x 6 LWIR array. Integration time for the measurement was 1.76 ms. Output voltage for the detectors was sampled every 100^th frame. 32,768 frames of time series data were collected for a total record length of 98 minutes. The frame average for a number of detectors was subtracted from each detector to correct for temperature drift and any common-mode noise. The corrected time series data was Fourier transformed to obtain the noise spectral density as a function of frequency. Since the total time for collecting the 32,768 time data series points is 98.0 minutes, the minimum frequency is 170 μHz. A least squares fit of the form (A/f + B) is made to the noise spectral density data to extract coefficients A and B that relate to the 1/f and white noise of the detector respectively. In addition noise measurements were also acquired on columns of SWIR detectors. Measurements were made under illuminated conditions at 4 mV and 50 mV reverse bias and under dark conditions at 50 mV reverse bias. The total collection time for the SWIR detectors was 47.7 minutes. The detectors are white noise limited down to ~10 mHz under dark conditions and down to ~ 100 mHz under illuminated conditions.

Proceedings Article | 21 October 2004 Paper

High-operating-temperature infrared detectors based on HDVIP

Franklin Roush, Hung-Dah Shih, Thomas Orent, Charles Franda, Peter Dreiske, Fikri Aqariden, Michael Kinch, Pok-Kai Liao, James Robinson, Herbert Schaake, Towfik Teherani, Arne Kalma

Proceedings Volume 5563, (2004) https://doi.org/10.1117/12.566371

KEYWORDS: Microlens, Silicon, Mercury cadmium telluride, Microlens array, Infrared detectors, Sensors, Etching, Mid-IR, Staring arrays, Diodes

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Proceedings Article | 21 October 2004 Paper

HDVIP for low-background-flux and high-operating-temperature applications

Paul LeVan, Franklin Roush, Hung-Dah Shih, Michael Kinch, Fikri Aqariden, Pok-Kai Liao, Peter Dreiske, Charles Franda, Thomas Orent, James Robinson, Herbert Schaake, Towfik Teherani, Arne Kalma

Proceedings Volume 5563, (2004) https://doi.org/10.1117/12.566370

KEYWORDS: Diodes, Mercury cadmium telluride, Metals, Mid-IR, Diffusion, Staring arrays, Liquid phase epitaxy, Doping, Mercury, Silicon

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Proceedings Article | 7 October 1994 Paper

Optical absorption coefficient of CdZnTe

A. Syllaios, Pok-Kai Liao, Brian Dean

Proceedings Volume 2274, (1994) https://doi.org/10.1117/12.189248

KEYWORDS: Absorption, Mid-IR, Cadmium, FT-IR spectroscopy, Tellurium, Temperature metrology, Annealing, Spectroscopy, Mercury cadmium telluride, Zinc

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Proceedings Article | 12 August 1992 Paper

Producibility of (Hg,Cd)Te by dipping liquid phase epitaxy

Luigi Colombo, Glenn Westphal, Pok-Kai Liao, M. Chen, Herbert Schaake

Proceedings Volume 1683, (1992) https://doi.org/10.1117/12.137777

KEYWORDS: Liquid phase epitaxy, Indium, Staring arrays, Doping, Tellurium, Chemical analysis, FT-IR spectroscopy, Liquids, Diodes, Mercury cadmium telluride

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Proceedings Article | 1 October 1990 Paper

Growth of (Hg,Cd)Te from Te-rich solutions

Luigi Colombo, Pok-Kai Liao

Proceedings Volume 1307, (1990) https://doi.org/10.1117/12.21706

KEYWORDS: Liquid phase epitaxy, Liquids, Crystals, Solid state electronics, Sensors, Interfaces, Mercury, Process control, Electro optical sensors, Tellurium

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Showing 5 of 9 publications

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