V.E. Lashkaryov Institute of Semiconductor Physics NAS of Ukraine
National Academy of Sciences of Ukraine


Sensors of infrared radiation

№26 Department of Physical Chemistry of semiconductor materials
A.V. Sukach

Worked out is the laboratory technology for manufacturing the sensors of infrared (IR) radiation from the spectral range λ = 1.0 – 3.6 μm. The sensitive element of these sensors is InAs p-n junction made using the diffusion method.

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The typical view of noncooled (a) and cooled (b) sensors of IR radiation


These noncooled sensors of IR radiation are designed for application in optoelectronic sensors aimed at revealing the leakage of natural gas from gasmains (in energetics and public utilities). The cooled sensors can be used in devices of medical thermography, scientific investigations as well as in educational process (laboratory experiments) in higher schools for training engineer-and-physicist personal within the system of the Ministry of Education and Science of Ukraine.

Description of the design.

The sensitive element of these sensors of IR radiation is made using diffusion of acceptor cadmium impurity into monocrystalline wafers of indium arsenide with n-type conductivity. Monocrystalline ingots of InAs were grown by the native producer Joint Stock Company “Чисті Метали” (Svetlovodsk, Ukraine). The regime of this sensor operation is photovoltaic (without using any bias voltage). The principle of its operation is based on the ability of the p-n junction electric field to separate electron-hole pairs generated by IR radiation in its sensitive area, which results in appearance of a photo-signal at the structure terminations.
       Contrary to existing analogous sensors, the sensitive element of the offered ones possesses lightly doped p0-n0 region. This improvement results in decreased recombination losses of non-equilibrium charge carriers inside the sensitive area and promotes realization of high operation parameters.

Main technical-and economical characteristics of the design.

Number Parameter and its measurement units Non-cooled Cooled
1 Operation regime Photovoltaic Photovoltaic
2 Operation temperature, K 295 80
3 Range of spectral sensitivity, μm 1.0 – 3.6 1.0 – 3.1
4 Peak of sensitivity, λmax , μm 3.4 – 3.5 2.9 – 3.1
5 Current-power sensitivity at λmax , A/W 0.5 – 0.6 1.0 – 1.1
6 Detectivity at λmax , cm.Hz1/2.W-1 (1.0 – 1.5).109 (6 – 7).1011
7 Product of the differential resistance at zero bias voltage by the active area, Ohm.cm2 0.15 – 0.20  (5 – 6).105
8 Active area, cm2 4.10-2 4.10-2
9 Response, s 3.10-6 2.10-7