Investigation of High-Temperature Diamond UV Photodetectors With MSM and SBD Structure Fabricated by Selectively Grown Method

This work systematically investigated the high-temperature performance of 3-D diamond ultraviolet (UV) photodetectors with metal–semiconductor–metal (MSM) and Schottky barrier diode (SBD) structures fabricated via a selective epitaxial growth method. The introduction of tungsten-related shallow impurity levels ( $\Delta {E}~\approx ~0.32$ eV) during selective growth within the diamond’s forbidden gap endowed the film with semiconducting properties, enabling temperature-dependent conductivity. At room temperature, the SBD detector demonstrated superior performance in the forward bias state, achieving a responsivity of 2162 A/W under a forward bias of 10 V, a ${R} _{{220}\,\text {nm}}$ / ${R} _{{400}\, \text {nm}}$ rejection ratio of 113, a rise time of 0.117 s, and a fall time of 4.4 s, which were better than those under reverse bias conditions and those of the MSM detector. When operating at $300~^{\circ }$ C, the SBD detector at forward bias state maintained exceptional stability, delivering an ultrahigh responsivity of 82612 A/W while retaining a high rejection ratio (164) and rapid rise time (0.053 s), albeit with a slightly prolonged fall time (5.83 s). In contrast, the MSM detector suffered from a slower temporal response at elevated temperatures, and the SBD detector at reverse state had a low responsivity and a fluctuating temporal response easily submerged by thermal noise. These results highlighted the robustness of the selective epitaxial growth method for fabricating 3-D diamond photodetectors and underscored the SBD configuration’s potential for extreme-environment applications.