Self-biased TiO2/Si heterostructure for UV-NIR detection via one-step laser ablation process

Abstract

This article elucidates a straight forward approach for the fabrication of self-driven, highly responsive broad-band TiO₂/Si heterojunction photodetector via one step laser ablation in water. In detail, the synthesized TiO₂ nanoparticles revealed the occurrence of average diameter of 22.43 nm along optical bandgap of 3.6 eV. The fabricated TiO₂/Si heterostructure exhibited a distinguished self-bias mode under illumination of 405 nm; this was perceived along $I_{ph}/I_D$ ratio reaching 10⁵, while the rectification ratio was found to be 288 under dark setting. Continuously, the fabricated heterostructure revealed a responsivity ($R_{\lambda }$) profile along UV-NIR region with peak values of 0.2 and 0.38 A/W at UV and NIR regions, respectively, indicating the active role of the utilized TiO₂ and Si layers; these values were obtained at zero bias volage evidencing the self-driven mode of the proposed geometry. The specific detectivity (D*) and external quantum efficiency (EQE) of $41\times {10}^{11}$ Jones and 65 % were attained at the NIR region, respectively.