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

One-dimensional (1D) metal oxides with excellent carriertransportand light absorption properties can be applied to photodetectors (PDs),facilitating device miniaturization, portability, and integration.Surface modification of 1D semiconductors can reduce carrier recombinationin PDs as a way to increase photocurrent and decrease dark currentof PDs. Herein, ultrathin BaTiO3 (BTO) shell layers aregrown on the surface of TiO2 nanorod arrays (NRs) by insitu conversion using hydrothermal reaction, and the self-poweredTiO(2)-BTO NRs PDs are constructed. The effect of the thicknessof BTO shell layers on the photoresponse characteristics of self-poweredTiO(2)-BTO NRs PDs is investigated by controlling the Ba2+ conversion concentration. The results show that the BTOshell layer reduces the dark current of the PDs because of the decreasedinterfacial transfer resistance and improved transfer of photogeneratedcarriers for building a "bridge" of carrier transportbetween BTO and TiO2 due to the formation of Ti-O-Tibonds. Moreover, the presence of the spontaneous polarization electricfield in BTO enhances the photocurrent and response speed of PDs.The self-powered TiO2-BTO NRs PDs are integrated in seriesand parallel to realize the functions of "and" and "or"gates of light-controlled logic gates. The ability to convert lightsignals into electrical signals for the self-powered PDs in real timedemonstrates its great potential for optoelectronic interconnectioncircuits, which has important application prospects in the field ofoptical communication.