Self-Powered UV Photodetector of TiO₂ with BaTiO₃ Surface Modification and Light-Controlled Logic Circuits Application

Abstract

One-dimensional (1D) metal oxides with excellent carrier transport and light absorption properties can be applied to photodetectors (PDs), facilitating device miniaturization, portability, and integration. Surface modification of 1D semiconductors can reduce carrier recombination in PDs as a way to increase photocurrent and decrease dark current of PDs. Herein, ultrathin BaTiO 3 (BTO) shell layers are grown on the surface of TiO 2 nanorod arrays (NRs) by in situ conversion using hydrothermal reaction, and the self-powered TiO 2 -BTO NRs PDs are constructed. The effect of the thickness of BTO shell layers on the photoresponse characteristics of self-powered TiO 2 -BTO NRs PDs is investigated by controlling the Ba 2+ conversion concentration. The results show that the BTO shell layer reduces the dark current of the PDs because of the decreased interfacial transfer resistance and improved transfer of photogenerated carriers for building a "bridge" of carrier transport between BTO and TiO 2 due to the formation of Ti−O−Ti bonds. Moreover, the presence of the spontaneous polarization electric field in BTO enhances the photocurrent and response speed of PDs. The self-powered TiO 2 -BTO NRs PDs are integrated in series and parallel to realize the functions of "and" and "or" gates of lightcontrolled logic gates. The ability to convert light signals into electrical signals for the self-powered PDs in real time demonstrates its great potential for optoelectronic interconnection circuits, which has important application prospects in the field of optical communication.

Integration of PbS Quantum Dots with 3D-Graphene for Self-powered Broadband Photodetectors in Image Sensors

“…Key parameters are compared in Table . R and D * are calculated using the following equations, respectively: , R = I light − I dark / P in × A D * = R × A 1 / 2 / false( 2 italiceI normaldark false) − 1 / 2 where I light is the photocurrent, I dark is the dark current, P in is the power density of the incident light, and A is the effective area of the device (5 × 10 –5 cm 2 ). Benefiting from the high light absorption characteristics of 3D-graphene and the effective modulation of the built-in potential by PbS QDs, the performance of the PD is prominently elevated.…”