High-performance ZnTe/Bi2O2Se heterostructure photodetector for optical imaging applications

Two-dimensional (2D) material heterostructure technology has been widely applied in numerous photodetectors due to its efficient light–matter interaction and versatile device construction. However, less attention has been paid to the coordinated optimization of photogenerated carrier dynamics, spanning generation, separation, and transportation procedures, which requires comprehensive consideration from both optical and electrical aspects. Here, we designed and fabricated a six-electrode ZnTe/Bi2O2Se heterostructure photodetector, which enables a direct comparison of the performance of three material configurations (ZnTe, Bi2O2Se, and the heterostructure) within a single device. The ZnTe nanoribbon, with its direct-bandgap structure, exhibits efficient light absorption and photogenerated carrier production. When combined with the high carrier mobility of Bi2O2Se 2D nanosheets, the heterostructure region demonstrates superior photoresponse under weak light illumination compared to the individual material regions; the responsivity reaches 107.6 A/W, more than twice that of the Bi2O2Se region. The stable photoresponse of the heterostructure region under low light intensity and low bias voltage makes it suitable for optical imaging applications. This work highlights the importance of heterostructure technology and device architecture design, providing insights for achieving high-performance photodetectors.