High-sensitivity flexible position sensing in a Cu(In,Ga)Se2 multi-layer heterojunction tuned by piezo-pyroelectric effect

Position sensitive detector (PSD), as an essential non-contact sensor on the basis of lateral photovoltaic effect (LPE), shows special superiorities in accurate positioning and sensitive light sensing. However, previous results are mainly based on rigid devices, and the LPE responses are still very deficient. In this manuscript, a Cu(In,Ga)Se2 (CIGS) multi-layer heterojunction of steel/Mo/CIGS/CdS/ZnO nanowire/ITO is developed as a high-performance flexible PSD. This PSD shows an excellent response in a broadband range of 405–1064 nm with position sensitivity (PS) up to 235.4 mV/mm and nonlinearity no more than 2.5 %. Moreover, it is demonstrated that piezoelectric and pyroelectric fields induced in the ZnO nanowire can substantially tune the band alignment and facilitate the longitudinal transport of the carriers, then give rise to a great improvement of the LPE responses. When the piezoelectric and pyroelectric effects are introduced, the best PS of 639.9 mV/mm is obtained with a significant enhancement of 171.8 % due to their favorable coupling mechanisms. Meanwhile, the response time is dramatically shortened to 6.8/7.9 μs. This work demonstrates that the piezo-pyroelectric effect shows huge potentials in developing high-performance ultrafast flexible PSDs.