| The technology of Ultraviolet(UV) detection possesses significant application value in the fields of flame detection, imaging technology and optoelectronic integrated circuits,and the ultimate study objective of researchers in the world is to fabricate high performance UV detector with fast response speed, low noise current and breakout detection sensitivity. Nowadays, though the breakthrough has been made in low dimensional nano-materials synthesis and high purity material preparation about wide band-gap semiconductors, the performance of UV detectors based on one single material has reached the bottleneck. As the heterojunction composites are gradually applied in the UV detection technology, the defects about low photo response and large dark current of UV photodetector could be improved. So the devices based on heterojunction have become the focus of research. In this work, the Ti O2/GO(grapheme oxide) and Ti O2/Zn O composite materials were prepared by using Ti O2 as the basis, and the two composite materials were applied in the UV detector. The photoelectric detection performance and the working mechanism of the heterojunction devices were deeply explored.In this study, the sol-gel method and droplet coating method were used to fabricate the Ti O2/GO heterojuncton material. The GO layer could block the transmission of electrons and promote the extraction of holes due to the well matched between Ti O2 and GO. At the same time, the gain of hole produced arising from the Ti O2/GO device would greatly improve the photoelectric performance of the detector. Moreover, a series of Ti O2/GO materials and devices with different GO distribution and thickness could be obtained by changing the parameters of GO layer preparation. Then, the properties of different devices were tested in detail, and the working mechanism of the devices was analyzed deeply to obtain the optimal device.The Ti O2 nanowires array was prepared on the surface of FTO substrate by hydrothermal method, then the Zn O nanoparticles were grown on the surface of Ti O2 by the crystallization precipitation method. The Ti O2/Zn O composite material is formed maintaining the one dimensional structure. The SEM results showed that the composite nano array material was compact and uniform, which was suitable for the fabrication of UV photodetector. By comparing the performance of Ti O2/Zn O device with bare Ti O2 device, it could be found that there was significant improvement in the photo responsivity and recovery time of the herojunction device. The relevant mechanism analysis and the mechanism of carrier transport were given detailedly. In addition, the red shift of spectral response exhibited by Ti O2/Zn O heterojunction device made the wavelength range of photo response adjustable.In this paper, two kinds of Ti O2 based heterojunction materials were prepared, and which were used in the field of ultraviolet detection technology. The heterojunction devices possessed great performance in photo response, response speed and sensitivity.The properties of the two heterojunction UV detectors were measured in detail, and the working mechanism of devices was studied in depth. This work not only laid the foundation for future research, but also opened up a wider research field of the UV detection technology. |
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