High Operating Temperature and Low Power Consumption Boron Nitride Nanosheets Based Broadband UV Photodetectors

摘要

Presently, novel scientific, industrial and military applications have resulted in a continuous increase in needs and expectations from the performance and capabilities of UV photodetectors that vastly exceeds those exhibited by current UV photodetectors. For instance, smart, flexible, self-powered and intelligent UV photodetectors are urgently needed in health, infrastructure, and environmental monitoring. Therefore, there is mounting pressure to create the next generation of high-performance (high sensitivity, fast response times, etc.) versatile UV photodetectors with increased miniaturization, mechanical flexibility and energy efficiency. Taking these facts into consideration, this work has attempted to fabricate deep UV photodetectors with films of BNNSs randomly orientated as the active WBGS material. Given the energy bandgap, mechanical robustness and chemical inertness of hBN, investigating the performance of a hBN based PDs could lead to a high-performance device with additional capabilities such as tolerance to high temperatures and exceptionally low power consumption.;Synthesized BNNSs on AlN and Si substrates were studied. Characterizations by X-Ray diffraction (XRD) and Raman spectrum analysis indicate that the material is composed of high purity hexagonal boron nitride (hBN). Scanning electron microscope (SEM) and Atomic force microscopy (AFM) images confirm this particular arrangement of BNNSs is made of randomly orientated hBN nanosheets. A significant shift in the cut off wavelength of the BNNSs based photodetectors was observed suggesting a band gap reduction as a result of the BNNSs' collective structure. The newly designed photodetectors presented exceptional properties: a high sensitivity to weak intensities of radiation in both UVC and UVB range while remaining visible-blind, and a high signal-to-noise ratio operation even at temperatures as high as 400 °C. In addition, the BNNSs based photodetector exhibited potential for self-powered operation.