Sb2Se3/p-Si position-sensitive detector has high sensitivity and fast response

A lateral-effect position-sensitive detector (PSD) based on an antimony selenide/silicon (Sb2Se3/p-Si) junction shows a position sensitivity of up to 448 mV/mm for visible/near-IR light.

Lateral-effect position-sensitive detectors (PSDs) are an essential component of many laser-optical systems, especially those that require some sort of beam alignment (quad-cell PSDs, which operate on a different principle, are also important). Researchers at the Harbin Institute of Technology (Harbin, China) have demonstrated PSDs using antimony selenide/silicon (Sb2Se3/p-Si) junctions fabricated using pulsed laser deposition (PLD) that exhibit a large lateral photovoltaic (LPV) effect that is linear with laser spot position with a maximum position sensitivity of up to 448 mV/mm and an optical relaxation time (1/e) for the LPV effect of 4.98 μs. Tested at light with wavelengths of 635, 780, and 808 nm, the high LPV and rectifying behavior of the room-temperature device makes it a promising candidate for many general-purpose applications in optoelectronics, say the researchers.

Sb2Se3 films with a thickness of 108 nm were deposited on three separate Si substrates with resistivity ranges of 500–100, 8–12, and 0.1–1 Ω·cm, respectively. The highest position sensitivity of 448 mV/mm was seen for a Si resistivity of about 8 to 12 Ω·cm. LPV data as a function of laser power from 1 to 40 mW was taken for the three test wavelengths, showing that the LPV saturates rapidly with laser power—at about 1 mW or so in the case of light at 635 nm. Reference: Y. Zhang et al., Opt. Express (2018);

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