The Electroluminescence Of ZnO Nanorod/organic Material Heterostructure Devices

ZnO is a promising material for short wavelength LEDs.The one-dimensional ZnO nanomaterial has been attracted more attention due to its special physical and chemical properties.In this thesis,ZnO nanorods are prepared by the simple method which can be used in the electroluminescent device and used to prepare ZnO nanorods / organic materials heterojunction electroluminescent devices in which ZnO is the light-emitting layer.Then ZnO nanorods are used as the field emission electrode to improve the brightness of the Solid state cathodoluminescence(SSCL) devices.In this thesis,firstly ZnO nanorods are grown by the two-step method on transparent electric glass substrates.And we succeeded to prepare the the length of ZnO nanorods is controlled to for being used in electroluminescent device by controlling the growth time.SEM demonstrates that most of the nanorods are wurtzite crystal structure, and are vertical to the substrate.The average diameter of rods is about 35 nm,and the length is about 130 nm.XRD pattern indicates that ZnO nanorods have a typical wurtzite structure and oriente in the c-axis direction.From the absorption spectra,we can observe the samples with a strong ultraviolet(UV) absorption around 368nm. Photoluminescence spectra of the nanorods show that there is a UV emission peak at 387 nm,which indicate the sample has a good quality.The UV-LED device is a research hotspot.In this thesis,the heterostructure devices based on as-grown ZnO nanorods and organic semiconductor materials are prepared as ITO/ZnO/ZnO nanorod/ organic semiconductor materials/Al.Under DC bias,the UV electroluminescence at 380 nm of ZnO band-edge emission is observed.In the electroluminescence spectra of the device:ITO / ZnO(60 nm)/ ZnO nanorods / MEH-PPV / Al,the ZnO band edge emission is predominant and stronger than other emissions.The mechanism of the ZnO band edge emission and background emission are discussed.SSCL is a kind of fire-new excitation mode.The luminescence exciting energy comes from the hot electron accelerated by the inorganic semiconductor layer.The beginning electronic source is an important factor limiting the brightness of the SSCL devices.ZnO nanorods have a great electronic transmission capacity and field emission capacity.In this thesis,a SSCL device in which ZnO nanorods acts as the field emission electrode are prepared,and their luminescent properties are investigated.