Photoelectric Effect Of Composite Of Poly Amino Acid And Znic Oxide?Indium Tin Oxide Nanostructure

Wide band gap semiconductors are named the third-generation semiconduc tor materials,having a band gap of not less than 2.3 eV.Besides,they have many excelle nt performance,such as high optical transparency,saturated electron drift velocity and small dielectric constant.Compared with the conventional silicon-based photodetectors,wide bandgap semiconductor devices can effectively address the "silicon limit" problem.The photoelectric effect is the basis of photoelectric detection technology.Research on the photoelectric effect of new material has important significance to develop new type of photoelectric devices.With a wide band-gap of 3.3~4.3eV at room temperature,ZnO and ITO are both considered as potential photo-electronic materials.Besides,both of them have good light transmittance and conductivity to fabricate photoelectric devices.Up to now,many scientists have attempted to utilize organic amines and polymers to produce a large change in electrical signal via simple means without introducing chemical dopants or charge separating layers into the channel material.In this thesis,ZnO nanowires and ITO nanowires are prepared,then a cationic polymer of poly-l-lysine(PLL)is uniformly applied to the surface of the nanowires layer to test whether the photoelectric effect of our nanomaterial devices can be enhanced by this combination.(1)The ZnO nanostructure with different morphologies are prepared by differe nt methods.I: The ZnO nanoparticles are fabricated by solution method with unifor m diameter.II: Using chemical vapor transport method,good performance ZnO nanowires are prepared on the substrate;III: Using chemical vapor transport method,ITO nanowires are manufactured with different length and the density by controlling the parameters of growing process.(2)Using ZnO nanowires platform combined with poly-l-lysine,a new type photodetector is fabricated.Then the device is il uminated by the xenon lamp?532nm?808nm and 1064 nm laser,the photocurrent respectively increase2.456?2.241?5.772 and 2.527 times compared to that of the non-PLL sample.The device has the most sensitive response to the green light.When the green light source was employed,the positive photoconductivity increase 12.86 times compared to that under the dark condition.Besides,when the sample which we dropped poly-l-lysine solution before was measured in the dark condition,the photoconductive effect is larger than the untreated sample with il umination.(3)Using ITO nanowires platform combined with poly-l-lysine,a new type of organic-inorganic hybrid device of photodetector is fabricated.First,compared to the non-PLL sample,the photo-generated voltage of PLL-treated device increase 33% when the detector was irradiated by 532 nm laser.The photo-generated voltage of PLL-treated device increase 3.33 times when irradiating the detector with 808 nm laser.Second,with a bias of-0.1V~0.1V at both ends of the detector,we find the photocurrent of detector under 808 nm and 532 nm lasers was increased several times bigger than that of the detector under dark condition.