Zhen Cui, Lannan Yan, Yuqiao Ren, Junliang Yao, Chenxing Liu
Abstract A comprehensive first-principles and density functional theory study was conducted to explore the band structure, differential charge redistribution, optical properties, and photoelectric detection characteristics of PtSSe/AlN heterojunctions. The results identify the PtSSe/AlN heterojunction as a structurally stable, type-II semiconductor, demonstrating an indirect bandgap of 1.53 eV, and representing a typical van der Waals heterojunction capable of efficient electron–hole pair separation. The internal electric field induced by the interface serves to lower the barrier height, thus promoting carrier injection. The application of strain maintains the type-II band alignment, ensuring high stability. Meanwhile, PtSSe/AlN heterojunctions have good light-harvesting capability in the ultraviolet to visible spectrum, exhibiting three pronounced absorption peaks within the visible spectral range. The self-powered photodetector based on this heterojunction achieves high photocurrent density under different polarized lights; when the incident light energy is 2.6 eV, the maximum value of the extinction coefficient is about 14. The results indicate the device’s versatility for applications, including in photoelectric detectors, optical modulators, and sensors. This research provides theoretical foundations for developing novel photodetectors, establishes a robust basis for experimental studies and device fabrication, and holds promise for advancing high-performance multifunctional optoelectronic devices.