The Fabrication And Photosensitive Properties Analysis Of Organic Dye Phthalocyanine Thin Film Transistor

Organic semiconductors have been extensively used in photoelectronics because of its advantages of lightweight,Thin film transistor(TFT)as a thin film transistor liquid crystal display(TFT-LCD)and active organic electroluminescent display(AM-OLED)core driving device has been studied positive.For the thin film transistor of TFT-LCD technology has been mature,but unlike the OLED driving method,thin film transistor in OLED is current driven,The current drive is in a fixed period of time the more into the carrier,the pixel is the more light and the better.So we prepared thin film transistor with vertical structure,the test result indicates that the output curve is unsaturated current trend,it's more conducive to the OLED display.In this paper we use organic lead phthalocyanine(PbPc)as the active layer.The material of PbPc semiconductor has good photosensitive properties.Excitons will be generated after the optical signal irradiation in semiconductor material,and then transform into photocurrent under the built-in electric field formed by the Schottky contact,as the organic transistor drive current,makes the output current enlarged.Organic material has Low carrier mobility,The vertical structure is more advantageous to the reduction of the thin film transistor conductive channel length,improve the transistor output current capability.First of all,PbPc powder is evaporated on the glass slide in the vacuum condition,We test the best deposition temperature and film thickness of organic material,film thickness is measured in the different deposition time corresponding;At the same time,We apply RF sputtering indium tin oxide(ITO),in order to get the best properties of ITO thin film.Then,We fabricated organic PbPc vertical structure thin film transistor,the transistor structure is Cu/PbPc/Al/PbPc/ITO,It's sandwich structure,the Cu,Al,and ITO are used as electrode,Applied DC/RF magnetron sputtering,and PbPc is prepared by vacuum evaporation.Al and PbPc form a Schottky contact,Cu/ITO and PbPc form ohmic contact.Using semiconductor tester test different PbPc thin film transistors with different active layer thickness,and the operating current can be as high as tens of microamperes.When active layer thickness is 40nm,the device has a good performance.Thin film transistor electrical properties of the output current under illumination,transfer characteristic curve,and current amplification coefficient were measured in full band white light and monochromatic light under the irradiation of 800nm.When Vce is 3V,full band white light amplification coefficient changes between 5.23-5.86,800nm monochromatic light amplification coefficient changes between 2.91-3.34.Amplification factor ? in no light is 20.23,the full band white light current IL is 0.910?A,it's 1.59 times the base current,the same 800nm monochromatic light current IL is 0.485 ?A,it's 1.30 times the base current;white light amplification coefficient IL is 86.87,800nm monochromatic light amplification coefficient IL is 61.42.Sensitivity is 0.1845A/W and 0.1968A/W,respectively.