高真空磁控溅射温度对Ga_(2)O_(3)微观结构及光学性能的影响

Effect of Sputtering Temperature on Microstructural and Optical Properties of Gallium Oxide Deposited by High-vacuum Magnetron Sputtering

采用高真空射频磁控溅射法在硅Si(111)衬底上沉积氧化镓(β-Ga_(2)O_(3)),开展了溅射温度对Ga_(2)O_(3)微观结构及光学性能影响的研究,利用X射线衍射、扫描电子显微镜、荧光光谱仪等测试手段对Ga_(2)O_(3)晶体结构、表面形貌及光学性能进行表征分析。实验结果表明,在高纯Ar气环境下,所沉积的Ga_(2)O_(3)形貌差异与不同溅射温度下Ga_(2)O_(3)生长机理有关,当溅射温度达到300℃时,Ga_(2)O_(3)发生热分解,形成金属Ga团簇;当溅射温度达到400℃时,金属Ga团簇作为催化剂触发Ga_(2)O_(3)纳米线的自催化生长。光致发光(PL)光谱中,Ga_(2)O_(3)样品在300~700 nm波长范围内显示出4个位于紫光、蓝光、绿光区域的发射峰,在溅射温度为400℃下形成的Ga_(2)O_(3)纳米线发射峰显著增强,并且发生轻微的蓝移,纳米结构中较大的比表面积以及量子尺寸效应对Ga_(2)O_(3)的荧光发射(PL)性能具有重要影响。拉曼光谱(Raman)显示,随着溅射温度升高,Ga_(2)O_(3)晶体质量有所提高;在溅射温度为400℃下形成的纳米线出现新的拉曼振动模式,并且发生18 cm^(-1)的蓝移。

Gallium oxide(β-Ga_(2)O_(3))was deposited on silicon(111)substrate by RF magnetron sput⁃tering,and the effect of substrate temperature on the microstructure and optical property of the Ga_(2)O_(3)was studied.The crystal structure,surface morphology and optical propery of as-deposited Ga_(2)O_(3)were characterized by X-ray diffraction,scanning electron microscopy,fluorescence spec⁃trometer,etc.The experimental results show that in a high-purity Ar atmosphere,the surface mor⁃phology of as-deposited Ga_(2)O_(3)is related to its growth mechanism at different sputtering tempera⁃tures.When the sputtering temperature is 300℃,Ga_(2)O_(3)undergoes thermal decomposition to form clusters of metal Ga;when the sputtering temperature reaches 400℃,the metal Ga clusters act as the catalyst to trigger the self-catalytic growth of Ga_(2)O_(3)nanowires.According to the photolumines⁃cence(PL)spectra,the Ga_(2)O_(3)samples show four emission peaks located in the ultraviolet,blue and green light regions in the spectral range of 300 nm to 700 nm.The emission peaks of the Ga_(2)O_(3)nanowires obtained at the sputtering temperature of 400℃are significantly enhanced and exhibit slight blueshifts.It is revealed that the larger specific surface area and the quantum size effects of nanow⁃ires have important effects on the PL performance of Ga_(2)O_(3).Raman spectroscopy(Raman)character⁃izations suggest that the crystalline quality of as-grown Ga_(2)O_(3)is improved with the increasing sputter⁃ing temperature.New Raman vibration modes appear in the spectra detected from the Ga_(2)O_(3)nanow⁃ires grown at 400℃,and the Raman peak shows a blueshift of 18 cm^(-1).