【作者】 吴玉新；

【导师】 薛成山；

【作者基本信息】 山东师范大学 ， 微电子学与固体电子学， 2006， 硕士

【摘要】 本文采用氨化磁控溅射Ga2O3/BN薄膜的方法在硅衬底上合成了大量的一维GaN纳米结构,通过研究不同生长条件对制备一维GaN纳米结构的影响,初步提出并探讨了采用此方法合成一维GaN纳米结构的生长机制。采用溶胶―凝胶法和电泳沉积法在砷化镓和硅衬底上制备出了GaN薄膜,研究了退火温度对GaN薄膜的结晶质量和表面形貌的影响。用射频磁控溅射系统,首先在硅衬底上制备Ga2O3/BN薄膜,接着在氨气气氛中退火制备一维GaN纳米结构。用X射线衍射(XRD)、傅里叶红外吸收谱(FTIR)、X射线光电子能谱(XPS)、扫描电镜(SEM)、高分辨透射电镜(HRTEM)和光致发光谱(PL)等测试手段详细分析了GaN纳米材料的结构、组分、形貌和光致发光特性。结果表明:合成的一维纳米结构为六方纤锌矿结构的GaN。氨化温度、氨化时间和BN层的厚度对一维GaN纳米结构的结晶程度和形貌具有很大的影响。室温下用320nm波长的光激发样品表面,显示出较强的373nm处的紫外光发射和434nm处的弱紫光发射,发光强度随氨化温度的升高而逐渐增强,但发光峰位基本保持不变。由于合成的大部分纳米结构的直径均大于GaN的玻尔激子半径(11nm),超出了量子限制效应起作用的范围,因此,对于373nm处的带边发光峰,与文献报道的GaN体材料的发光峰相比,没有发生蓝移。对于紫光发射可归结为缺陷或表面态发光。有关的发光机制还在进一步的研究中。一维GaN纳米结构的生长机制可归结为气体―固体(VS)生长机制,其中BN中间层在氨化过程中由于重组而产生的缺陷和位错为GaN晶核的形成起到了至关重要的作用。采用溶胶―凝胶法分别在砷化镓和硅衬底上制备出了GaN薄膜。分别用XRD、XPS、SEM和PL等测试手段对样品的结构、表面形貌和光致发光特性进行了表征。结果表明:经高温退火后,样品发生晶化,并生成六方纤锌矿的GaN。随着退火温度的升高,晶粒尺寸变大,晶体质量逐步提高。其中退火温度为950℃时,样品的结晶质量和表面形貌最好。室温下,在波长为280nm光的激发下,可以观察到更多还原

【Abstract】 In this paper, one-dimension GaN nanostructures were synthesized on Si substratesby ammoniating Ga2O3/BN films. The growth mechanism of these GaN nanostructureswas proposed and discussed based on the investigation of the influence of theammoniating temperature, ammoniating time and the BN films’ thickness on theproperties of GaN nanostructures. GaN films were prepared on GaAs and Si substratesby sol-gel method and electrophoretic deposition technique, and the effects of theannealing temperature on the crystalline quality and morphology properties of the GaNfilms were discussed.One-dimension GaN nanostructures were fabricated on Si(111) substrates throughammoniating Ga2O3/BN films deposited by ratio frequency (RF) magnetron sputteringsystem. The structure, elemental composition, morphology and photoluminescenceproperties of the GaN nanostructures were determined by X-ray diffraction (XRD),Fourier transformed infrared spectroscopy (FTIR), X-ray photoelectron energyspectroscopy (XPS), scanning electronic microscope (SEM), high-resolutiontransmission electronic microscope (HRTEM) and photoluminescence spectroscopy(PL). The results showed that the as-synthesized one-dimension nanostructures werehexagonal GaN with wurtzite structure. The ammoniating temperature, ammoniatingtime and the thickness of the BN films greatly affected the crystalline quality,morphology and photoluminescence properties of the GaN nanostructures. A strongemission peak at 373nm (ultraviolet band) and a weak emission peak at 434nm (violetband) were found from the GaN nanostructures, which were excited by 320nm light atroom temperature. It was found that the PL intensity of the two emission peaksenhanced with the increase of the ammoniating temperature and time, and the positionsof them had no change. Because the as-prepared GaN nanostructures is too large forquantum confinement, and in fact the Bohr exciton radius of GaN is 11nm. Theemission peak at 373nm has no blue shift of the band-gap emission compared with thebulk GaN. Another emission peak at 434nm may be attributed to the existence ofdefects or surface states. Further detail work is needed to clarify the underlyingmechanism for the PL spectrum of the one-dimension GaN nanostructures. The growthmechanism of the one-dimension GaN nanostructures can be explained as thevapor-solid growth mechanism, of which the BN films play a very important role in theformation process of the GaN crystal nuclei.GaN films were grown on GaAs and Si substrates by sol-gel method. XRD, XPS,SEM and PL were used to analyze the structure, morphology and photoluminescenceproperties of the GaN films. The results showed that high-temperature annealing madefor the crystallization of the GaN crystals. The diameters of the GaN crystallites becamelarger and the crystal quality of the GaN films was improved with the increase of theannealing temperature. The samples annealed at 950℃ for 10min exhibited the bestcrystal quality and morphology. Under 280nm photo-excitation, a strong emission peakat 385nm, as well as two weak emission peaks at 440nm and 475nm, was observed. ThePL intensity of the emission peaks increased with the increasing of the ammoniatingtemperature. The emission peaks at 440nm and 475nm can be ascribed to the radiantcombination from conduct band to the energy level of acceptor impurity. Further detailwork is needed to clarify the underlying mechanism for the PL spectrum of the GaNfilms grown by sol-gel method. Some clusters of nanowires appear on the surface of thesamples annealed at 1000℃ for 10min on Si substrates. Every cluster of the GaNnanowires was grown along a radiant direction. These nanowires were very straight andsmooth, being identified to be hexagonal wurtzite structure GaN single crystal.GaN films were deposited on Si(111) substrates by electrophoretic depositiontechnique, and the effects of the annealing temperature on the properties of the as-grownGaN films were investigated. The structural, compositional, morphologic andluminescent properties of the GaN films were studied in detail. The results indicatedthat the annealing temperature had a great effect on the crystal quality, morphology andphotoluminescence properties of the GaN films.更多还原