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I am currently searching the InGaAs material for infrared imaging usage. I have read some papers about it. It seems a new one. But I can not get real advantages of it, yet. What is the basic reason(motivation) of usage this material in infrared imaging systems?

Best Regards,

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    \$\begingroup\$ Google search of "InGaAs vs Silicon" is returning 400K results. \$\endgroup\$
    – Eugene Sh.
    Dec 14, 2017 at 20:21
  • \$\begingroup\$ what research have you done? \$\endgroup\$
    – jsotola
    Dec 14, 2017 at 20:41

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Silicon detectors have a low responsivity with wavelengths higher than 1000 nm. "Infrared" cover a large part of the electromagnetic spectrum. For a part of that spectrum, around ~1µ to ~2µ, InGaAs have a good responsivity and low noise at a reasonable cost. InGaAs detectors are not new, they already existed in the 80s.

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  • \$\begingroup\$ Dear @pserra, Thank you for reply. Responsivity seems as 'gain' in amplifier terminology. It is understood that from here an InGaAs infrared detector produced much more Electrical signal than an Silicon-based infrared detector, for the same amount of Photon as input. Sure, it is not new. But nowadays many Infrared detectors are still fabricated on Si-based. So probably there may be still some another disadvantages of InGaAs infrared detectors w.r.t to the Si-based ones. \$\endgroup\$
    – doner_t
    Dec 16, 2017 at 12:09
  • \$\begingroup\$ I would not say that InGaAs infrared detectors produce much more electrical signal than a silicon-based detector. If you are in the short infrared, below 1µ, then silicon could be superior. For example, an silicon avalanche photo-diode (APD) can reach an avalanche gain of more than 100 while an InGaAs APD will typically reach 20. If your detector have no internal gain, the signal-to-noise ratio is a more important metric than raw gain. In the end, it really depends of the wavelength. \$\endgroup\$
    – pserra
    Dec 17, 2017 at 0:35
  • \$\begingroup\$ Hello @pserra, Thank you for reply. InGaAs material is also reported such as high-speed. What do you think about the this "high-speed" term. For example high-speed InGaAs photodiode. However I am interested in InGaAs Infrared detectors. Does InGaAs IR detectors have higher response time than Silicon-based ones? Can It be thought as higher frame per second (fps) ? \$\endgroup\$
    – doner_t
    Dec 18, 2017 at 20:33
  • \$\begingroup\$ Small InGaAs diodes can be very fast, individual InGaAs detectors can reach bandwidth of 100 GHz, but Si detectors can still reach 1 GHz. For imagers with a shutter (a clocked array of detector), the substrate is not the limiting factor but the process and ADCs are more import. Silicon imagers can be vastly superior in term of resolution, cost, frame rate and functionalities because of commercial demand and much more refined process. \$\endgroup\$
    – pserra
    Dec 18, 2017 at 23:00
  • \$\begingroup\$ Helle @pserra, Thank you for reply. InGaAs material seen widely used in fiber optical Transmitters and Receivers, as Photodiodes and Photodetectors. InGaAs Photodiodes are in PIN form. (P-type, intrinsic, N-type). Sure, BW of these material is large w.r.t to the Si. So that means we can capture IR images by using this InGaAs material at the high frame per seconds. \$\endgroup\$
    – doner_t
    Dec 23, 2017 at 9:31

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