High-responsivity photodetectors made of indium selenide with visible to near-infrared photodetection

This study demonstrates indium selenide (InSe) photodetectors (PDs) with a broadband photodetection range from the visible to the near-infrared (NIR) region (400–1000 nm). The InSe flakes exfoliated from bulk material are transferred to a sapphire substrate, followed by the deposition of Ni/Au bi-layer metal contact to fabricate the metal-semiconductor–metal (M-S-M) PDs. In addition to an absorption edge at around 1000 nm, a strong absorption edge at around 516 nm is observed from the typical spectral response taken from the fabricated InSe M-S-M PDs. Under a bias voltage of -1 V, the typical responsivity at 400 nm is as high as 1130 A W-1, corresponding to a photoconductive gain of approximately 3500. Thus, InSe has potential application in broadband photodetection from the NIR to the visible region.