Surface plasmon assisted high-performance photodetectors based on hybrid TiO₂@GaO_xN_y-Ag heterostructure

Abstract In this work, we reported a high-performance-based ultraviolet-visible (UV-VIS) photodetector based on a TiO 2 @GaO x N y -Ag heterostructure. Ag particles were introduced into TiO 2 @GaO x N y to enhance the visible light detection performance of the heterojunction device. At 380 nm, the responsivity and detectivity of TiO 2 @GaO x N y -Ag were 0.94 A/W and 4.79 × 10 9 Jones, respectively, and they increased to 2.86 A/W and 7.96 × 10 10 Jones at 580 nm. The rise and fall times of the response were 0.19/0.23 and 0.50/0.57 s, respectively. Uniquely, at 580 nm, the responsivity of fabricated devices is one to four orders of magnitude higher than that of the photodetectors based on TiO 2 , Ga 2 O 3 , and other heterojunctions. The excellent optoelectronic characteristics of the TiO 2 @GaO x N y -Ag heterojunction device could be mainly attributed to the synergistic effect of the type-Ⅱ band structure of the metal–semiconductor–metal heterojunction and the plasmon resonance effect of Ag, which not only effectively promotes the separation of photogenerated carriers but also reduces the recombination rate. It is further illuminated by finite difference time domain method (FDTD) simulation and photoelectric measurements. The TiO 2 @GaO x N y -Ag arrays with high-efficiency detection are suitable candidates for applications in energy-saving communication, imaging, and sensing networks.