Preparation And Photoelectric Detection Properties Of Vanadium Oxide

Vanadium oxides show potential application in photoelectronic devices for their wide energy gap distribution,and among them,vanadium oxides with one-dimensional nanostructured with good photoelectric properties have been verified.However,the intrinsic drawbacks of one-dimensional material,like big resistance,small working area,and low photocurrent limited their practical application in photoelectronic devices.In comparison,the two-dimensional nanostructured vanadium oxides,such as net work structure and orderly arrays structure,will be easy to be integrated in large-scale devices for their group effects of single wires.Based on the above consideration,we fabricate various vanadium oxide with different morphologies and sizes,then investigate the building of ordered nanostructure with large area,and eventually studies the photoelectric properties of the two-dimensional nanostructured vanadium oxides.The main work in our research are listed as follows:(1)Solid and hollow vanadium dioxide spheres with uniform size are fabricated respectively,and these spheres can be assembled as single layered sphere film.The photodetector based on the single layered solid and hollow sphere film were constructed.It shows that the photodetector based on solid sphere film has better performance than hollow ones.(2)VO2(A)nanowires with high crystallization and orientation are fabricated by hydrothermal method,based on which single nanowire and nanowire film VO2(A)photodetector are prepared.It shows that the responsivity of nanowire film photodetector is 15.9 times of single nanowire photodetector at the same measure conditions.(3)Large scale and highly ordered vanadium dioxide nanowire arrays were successfully prepared by using the improved self-assembly method.The nanowires were arranged parallel in the same direction and formed into a uniform and compact structure.Different from the reported assembly process,in which surface pre-modification of the nanowires with organic assistant is a significant essential step.The driving force of self-assembly was provide by pressure difference from the volatilization of chloroform.Remafkable,the array length and width cover a large area,and can achieve the level of square millimeters.By controlling the precursor concentration of the nanowire solution and the assembly time,multilayer ordered nanowire arrays can also be achieved.The photodetector base on this ordered VO2 nanowire film shows a responsivity of 0.83 mA/W.Furthermore,ordered VO2(M)nanowire arrays are fabricated by annealing the VO2 nanowire films in N2 atmosphere,the photodetector based on this VO2(M)nanowire film shows a responsivity of 0.29 mA/W,and rise and fall time of 327 and 1-23 ms.(4)VO2/CNT composite film is fabricated by the hydrothermal method,and the photodetector based on this film is constructed.It shows that the performance of this photodetector is enhanced by CNTs.(5)Based on the self-assembly method,an ordered W doped VO2(M)nanowire arrays were prepared.The W-doped VO2(M)nanowire arrays shows better infrared detection property,the photocurrent of the photodetector is 1.2 ?A,resulting in a responsivity of 21.4 mA/W,which is higher than the pure VO2(M)nanowire arrays.(6)Ordered V2O5 nanowire arrays are fabricated by annealing from VO2 nanowires,and the photodetector based on these V2O5 nanowire arrays shows a responsivity of 160.3 mA/W,detectivity of 6.5×108 Jones,rise and fall time of 327 and 123 ms.