Studies On The Properties And Preparation By Sol-gel Method Of The Zn_1-xMg_xO Thin Films

Zinc oxide is a new-styledⅡ—Ⅵwideband gap(3.30eV) semiconductor material. It has comparatively large exciton bindingenergy(60 meV) and can be excited to emit by ultraviolet at the room temperature. Therefore, ZnO is a kind of very promising material for making the ultravioletoptoelectronic devices and greatly deserves being developed and put in application. Especially, the discovery of ultraviolet-excited emission of ZnO film makes it the hot topic among the semiconductor material researches both at home and abroad. Traditionally, ZnO is used as surface acoustic wave devices(SAW), bulk acoustic devices(BAW), gas sensors, varistors, transparent electrodes, UV-detectors, and etc. In recent years, ZnO has gained more and more attention as a wide band semicodductor. Compared to other wildly studied wide band semiconductor, ZnO is promising: high-quality ZnO with very low defect densities can be synthesized at much lower temperature; ZnO can emit light with shorter wavelength than blue light emission from GaN; ZnO has higher excitonic binding energy promising strong photoluminescence from the band excitonic emissions even at room temperature; Because the single crystalline of ZnO is difficult to form, high in price and small in size, it can not meet the needs of various applications. Therefore, the research and development of ZnO film production technology is an important direction among the application researches of ZnO material and devices. At present, MBE and PLD are among very good film-developing technology, but their cost is too high, making it difficult to bepresseo to film in a large size.This thesis adopts the method of Sol-Gel to develop ZnO and ZnMgO alloying film and introduces the influence of technology parameters such as calefactive velocity, film thickness, anneal temperature on the performances of the film such as crystalline quality and photoluminescence in a detailed way. Following is the main content:1. ZnO film is developed on glass Substrates using Sol-Gel technology usin(using different organic solvent). X-Ray Diffraction(abbreviated as XRD) result shows that all the films is in the structure of hexagonal wurtzite. But ZnO film prepared with 2-Methoxyethanol develops freely; ZnO film prepared with PVA displays the specific properties of growing in (002) preferentially oriented direction.2. The testing result of photoluminescence spectra at room temperature shows that all the samples have two emission bands, that is UV emission band near the band-edgeand visible emission band. With the rising of annealing temperature, UV emission increases and visible emission decreases gradually. When the anneal temperature is 600℃, The intensity of UV emission is biggest and there is nearly no visible emission observed.3. The testing of optical absorption spectra of the ZnO film on the glass substrate shows that the sample has a steep absorption edge at about 380 nm whose energy value is 3.20 eV. The testing of the transmittance spectra of the ZnO film shows the average percentage of the sample within the range of the visible light is 85%.4. Themethod of Sol-Gel is adopted to produce the Zn_1-xMg_xO (x=0.1, 0.2,0.3, 0.4,0.5,0.6,0.7) alloying thin film. XRD shows: when the value of x is between 0.1 and 0.3, the alloying thin film remains the structure of hexagonal wurtzite and the angle of (002) diffraction peak becomes bigger as the value of X increases; The photoluminescence spectra at room temperature shows that the PL spectra of the alloying thin film is composed of the stronger UV emission band and weaker visible band, and UV emission peak will have the blue shift with the content of Mg increasing and the visible emission weakened.