Pyroelectric-Enhanced Position Sensing and Its Multifunctional Imaging in a Si Nanowire/CdS Core-Shell Heterojunction

Three different Si/CdS heterojunction position-sensitive detectors with planar, pyramid, and nanowire structures are successfully prepared and systematically investigated. Among these configurations, the nanowire core-shell structure demonstrates superior self-powered capability and exceptional lateral photovoltaic effect (LPE) performance, achieving a broad optical response from 405 to 1064 nm, a peak positional sensitivity of 779.1 mV/mm, and a minimal nonlinearity of just 6.3%. Notably, introducing a pyroelectric effect improves the sensitivity to a record value of 11 646.7 mV/mm with an impressive enhancement of 1494.9%, alongside ultrafast response times of 92 and 103 μs. Furthermore, by exploring the relationship between the LPE response and laser wavelength, a PE-enhanced imaging system is developed, enabling discernment of various wavelengths. Despite the LPE response decreasing with increasing electrode spacing, an ultralarge sensitivity of 1177.6 mV/mm can still be achieved at a 6 mm working distance. More importantly, this unique characteristic can be utilized to modulate the imaging resolution, presenting diverse brightness levels under identical irradiation conditions.