Study On Back Incident Au/Zr_xTi_1-xO₂/Au Schottky Junction Ultraviolet Detector

In recent years, with the development of one-dimensional nanomaterial synthesistechnology, the devices of nanomaterial are more and more popular in photocatalysis anddye-sensitized solar cells, such as TiO2nanowire. However, due to the growth process ofnanowire is not easy to control and its smaller size, there are still some difficulties andchallenges in design and production of high-performance nanowire-based ultraviolet （UV）detectors. To solve these problems, this paper proposes a new type of nanowire-based UVdetector----back incident Schottky structure.In this thesis, a low-temperature hydrothermal method is used to direct synthesizedifferent titanium-zirconium ratio of Zr_xTi_1-xO₂nanowire arrays on FTO （F: SnO₂） transparentconductive substrate. X-ray diffraction （XRD）, UV absorption spectrum （UV-vis）, Scanningelectron microscopy （SEM） and X-ray photoelectron spectroscopy （XPS） are used tocharacterize the surface morphology and crystal structure of Zr_xTi_1-xO₂nanowire arrays. Also,the variation of nanowire performance is discussed by the influence of different growthconditions. With the base material of Zr_xTi_1-xO₂nanowire arrays, back incidentAu/Zr_xTi_1-xO₂/Au Schottky junction UV detector is presented by traditional photolithographyand magnetron sputtering technology. Besides, the dark current, optical responsivity, quantumefficiency and response time were all tested and analyzed.Zr_xTi_1-xO₂nanowire arrays grown on FTO substrate belongs to rutile crystalline phase,which is well matched with rutile FTO substrate and gets a good adhesion. From SEMphotographs, we can see that Zr_xTi_1-xO₂nanowires are arranged in dense and highly ordered,with an average particle size of about35nm, and a length of about1.2μm. And the surface ofarrays is smooth, which can fully meet the basic requirements of the device fabrication.When2V bias voltage is applied on back incident Au/Zr_0.2Ti_0.8O₂/Au Schottky junctionUV detector, the dark current of the device is only3.5nA. With the irradiation of360nm UV,the photocurrent can reach704nA; the responsivity is0.162A/W; and the correspondingquantum efficiency is56.2%. What’s more, the response time is about1.2s; and the recoverytime is approximately2.1s. So, this kind of back incident UV detector structure can achievequick photoresponse, high signal-to-noise ratio, large optical responsivity and quantumefficiency, which laid a good foundation for the development of nanowire-based UVdetectors.