A New Strategy of Coupling Pyroelectric and Piezoelectric Effects for Photoresponse Enhancement of a Cu(In,Ga)Se₂ Heterojunction Photodetector

Abstract Pyro/piezoelectric effects are thought as essential ways to modulate photoresponses of optoelectronic devices, but the pyro/piezoelectric materials usually function as photoactive or fundamental band matching layers. In this manuscript, a Cu(In,Ga)Se₂ (CIGS) multilayer heterojunction of Glass/Mo/CIGS/CdS/ZnO nanowire/ITO is prepared as a self‐powered photodetector (PD). The PD exhibits excellent performances in 405 to 1064 nm with maximum responsivity (R) of 0.455 A W⁻¹, and detectivity (D) of 7.22 × 10¹¹ Jones at zero bias. More importantly, the temperature variation‐induced pyroelectric field in the non‐photoactive ZnO layer is demonstrated to facilitate the transport of carriers. After introducing the pyroelectric effect, the responsivity (R) and detectivity (D) are largely increased to 4.92 A W⁻¹ and 7.81 × 10¹² Jones, respectively, and an ultrafast response time of 67.13/78.57 µs is obtained. Meanwhile, the response wavelength is extended to 1550 nm, which is far beyond the spectral limitation of the heterojunction. Besides, the piezoelectric effect of the ZnO nanowire can further optimize the band alignment and then boost the photovoltaic and pyroelectric responses. Owning to the favorable three‐synergistic mechanisms, the best R of 7.22 A W⁻¹ and D of 1.17 × 10¹³ Jones are observed, which are enhanced by 1586.8% and 1620.5%, respectively, and the response time is also shortened to 50.17/60.65 µs.