Preparation And Photoelectric Properties Of Poly Amino Acid Modified Cuprous Oxide Nanostructure

Cu₂O as a P-type semiconductor material,having a forbidden band gap of 2.0².2eV,can effectively absorb visible light,and has been widely used in the field of optoelectronics.In this thesis,the properties of nanostructure Cu₂O based optoelectronic devices modified by poly-L-lysine（PLL）were investigated.The related results are listed as follow:1、By optimizing the experimental parameters,Cu₂O nanoparticles and nanowires are fabricated.The size of the particles is from 200 to 400nm.The diameter of the nanowires ranges from 85 to 130nm,and the length of nanowires varies from tens to hundreds of microns.2、The photoelectric properties of ITO/Cu₂O nanoparticle modified by poly-L-lysine（PLL）combination were also investigated.The current response of ITO/Cu₂O devices is significantly improved by PLL modification.Under the bias voltage of+0.5V,the current response of the composite device in dark,illuminated by xenon lamp,532nm and 808nm lasers are 3.3,1.7,4.5 and 3.77 times higher than that of the no PLL modified device respectively.3、The influence of PLL on the photoelectric properties of Si/Cu₂O nanowires is studied.The amplitude of photovoltaic response increased from 48mV to 60mV and response time reduced from 15ms to 10ms.In addition,the position sensitivity of the device is measured.As the spot moves from the L terminal（the electrode is connected to the Cu₂O layer）to the R terminal（the electrode is connected to the Si substrate）,the amplitude of the photovoltage linearly decreases.This light spot position-sensitive platform is expected to serve as a convenient device as easily to be fabricated,high performing photodetector.4、The response of nanowire Cu₂O/Si heterojunction to humidity is also investigated.Changing the relative content of hot steam,the device produces an amplitude response signals with a positive correlation.When the relative humidity of about 50%,the response signal value remains unchanged.This indicates that nanowire Cu₂O/Si heterojunction can be used as a humidity detector.