Performance-Enhanced 4H-SiC BJT UV Phototransistor With Controllable Platinum Nanoparticles

Silicon carbide (SiC) ultraviolet (UV) phototransistor detectors (PTDs) with platinum (Pt) nanoparticles (NPs) were fabricated and analyzed in this article. We realized a controllable variation of the average diameter of Pt NPs in 40–100-nm range by changing the experimental conditions. Under 280-nm UV illumination, the responsivity of the PTD with 50-nm Pt NPs has reached 0.257 A/W and the quantum efficiency has reached 113.8%, which is 2.47 times higher than the PTD without Pt NPs. In contrast, the PTD with 100-nm Pt NPs has a responsivity of 0.174 A/W and a quantum efficiency of 77.1%, which is 1.67 times higher than the PTD without Pt NPs. For the switching characteristics, due to the electric field enhancement effect of the localized surface plasmon resonance (LSPR), the turn-on time of the PTDs with Pt NPs is shortened by 7%–14% compared to the PTD without Pt NPs. In addition, it is found that PTDs with larger sized NPs have larger probing currents at a deep-UV wavelength, a phenomenon that can be explained by advanced resonances induced by the changes in NP size. This result can also provide ideas for SiC probing at short-wave UV region (UVC).