Photoelectric characteristics of hydrogen-terminated polycrystalline diamond MESFETs

In the field of diamond MESFETs, this work is what we believe to be the first to investigate the optoelectronic properties of hydrogen-terminated polycrystalline diamond MESFETs under visible and near-UV light irradiation. It is shown that the diamond MESFETs are well suited for weak light detection in the near-ultraviolet region around the wavelength of 368 nm, with a responsivity of 6.14 x 10(6) A/W and an external quantum efficiency of 2.1 x 10(7) when the incident light power at 368.7 nm is only 0.75 mu W/cm(2). For incident light at 275.1 nm, the device's sensitivity and EQE increase as the incident light power increases; at an incident light power of 175.32 mu W/cm(2) and a VGS of -1V, the device's sensitivity is 2.9 x 10(5) A/W and the EQE is 1.3 x 10(6). For incident light in the wavelength range of 660 nm to 404 nm with an optical power of 70 mu W/cm(2), the device achieves an average responsivity of 1.21 x 10(5) A/W. This indicates that hydrogen-terminated polycrystalline diamond MESFETs are suitable for visible and near-UV light detection, especially for weak near-UV light detection. However, the transient response test of the device shows a long relaxation time of about 0.2 s, so it is not yet suitable for high-speed UV communication or detection. (c) 2023 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement