Ultrabroadband, Large Sensitivity Position Sensitivity Detector Based on a Bi2Te2.7Se0.3/Si Heterojunction and Its Performance Improvement by Pyro‐Phototronic Effect

Abstract Bi2Te(/Se)3, as a novel topological insulator, is a prospective candidate for next‐generation spintronic and photoelectric devices. Here, A series of Bi2Te2.7Se0.3 films are successfully prepared on Si substrate with different thicknesses and used as a self‐powered light position sensitive detector (PSD) through the introduction of a lateral photovoltaic effect (LPE). Owing to its wide and strong absorption, the high surface mobility of the Bi2Te2.7Se0.3 layer, and the outstanding heterojunction quality, this PSD shows an unprecedentedly broadband photoresponse from ≈350 to ≈2200 nm and exhibits very good performance with ultralarge sensitivities (283.71 mV mm−1 at 532 nm, 137.4 mV mm−1 at 1064 nm, 38.91 mV mm−1 at 1550 nm, and 16.56 mV mm−1 at 2200 nm), perfect nonlinearity (<3%), and ultrafast response times (≈52.1 µs/≈70.2 µs), all of which are among or represent the best results reported until now, especially in the infrared region. Additionally, its sensitivity can also be greatly improved though the addition of a bias voltage with an increment up to 194.6% at −1 V. More importantly, the pyro‐phototronic effect, which can be used to modulate both the LPE and the time response, is surprisingly observed in this PSD but with different working mechanisms than found in traditional photodetectors.