Hot Carrier Photocurrent through MOS Structure

Flow of photocurrent through the metal-oxide-semiconductor structure induced by the pulsed infrared CO2 laser is investigated experimentally. In the case of a perfect insulator, the photocurrent has a photocapacitive character. Its rise is based on the hot carrier phenomenon; no carrier generation is present, only redistribution of laser-heated carriers takes place at the semiconductor surface. The magnitude of this displacement current is related to the capacitance of the structure and is dependent on the rate of the laser pulse change as well as on the laser light intensity. This effect can find application in the detection of fast infrared laser pulses as well as in the development of infrared photovaractors. Operation of such devices would not require cryogenic temperatures what is usually needed by the long-wavelength infrared semiconductor technique.

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Thermally activated current–voltage asymmetry in quantum-well inter-subband photodetectors

Canadian Journal of Physics ◽

10.1139/p96-822 ◽

1996 ◽

Vol 74 (S1) ◽

pp. 9-15 ◽

Cited By ~ 8

Author(s):

P. V. Kolev ◽

M. J. Deen ◽

H. C. Liu ◽

Jianmeng Li ◽

M. Buchanan ◽

...

Keyword(s):

Quantum Well ◽

Carrier Transport ◽

Transport Phenomena ◽

Infrared Region ◽

Avalanche Photodetectors ◽

Long Wavelength ◽

Hot Carrier ◽

Thermally Activated ◽

Current Voltage ◽

Long Wavelength Infrared

Continuing research interest in quantum-well inter-subband-based devices can be associated with its prospects for numerous optoelectronic applications in the long wavelength infrared region. This paper presents experimentally measured field dependence of the thermally activated effective-barrier lowering in quantum-well inter-subband photodetectors (QWIPs). This barrier lowering is considered to be the main cause of the commonly observed asymmetry in the current–voltage characteristics of QWIPs. The research results presented here are important for understanding the factors determining the dark-current mechanisms that are crucial for further improvement in the characteristics of these devices. The study of current-carrier transport phenomena in a quantum well is also of interest for developing quantum-well lasers and avalanche photodetectors based on intraband processes, and also transistors based on ballistic or hot carrier transport phenomena.

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Effects of the Particle Size Variety of Metal Oxide on the Absorption Property of Long-Wavelength Infrared Laser

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.418-420.536 ◽

2011 ◽

Vol 418-420 ◽

pp. 536-539 ◽

Cited By ~ 1

Author(s):

Wei Fu Wang ◽

Yu Gui Zheng ◽

Jian Hua Yao ◽

Miao Zhang

Keyword(s):

Particle Size ◽

Aggregate Size ◽

Absorption Property ◽

Feedback Effects ◽

Long Wavelength ◽

Laser Absorption ◽

Large Particles ◽

Heated Area ◽

Laser Heated ◽

Long Wavelength Infrared

In order to study the influences of aggregate size on CO2laser absorption property, several special absorbing coatings were prepared from four kinds of different particle sizes (45 μm, 13 μm, 6.5 μm and 1.6 μm) TiO2powder. The CO2laser absorption capacities of these coatings were studied by comparative analysis of the surface morphology and laser heated areas. The results show that the absorbing capacity increases with particle size dwindling. In all samples, the 1.6 μm specimens display the best performance with the largest laser heated area on cross section. The analysis indicate that, the decreasing of particle size will lead to an increase on absorbing surfaces, which is benefit for improving the absorbing capacity. Furthermore, smaller size particles also can cause the temperature increased faster than large particles, which lead to a further increase on absorbing performance for the positive feedback effects between the temperature and the absorbing capacity. Finally, the effects of particle size variety on designing absorbing coatings are also discussed.

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