摘要
利用热氧化法在不同参数条件下生长了Ga掺杂范围较宽的ZnO薄膜,研究了ZnO薄膜的表面微观结构和光致发光性能.研究表明:Ga以Ga3+存在并掺入ZnO晶格取代Zn2+,Ga的掺入改变了Zn O薄膜中的缺陷类型及浓度、化学计量比、薄膜表面结晶质量,进而影响了薄膜的光致发光性能.随着热氧化温度升高,Ga掺杂量增大,ZnO薄膜的晶粒尺寸增大,尺寸更均一,紫外光与可见光强度比增大.随着热氧化时间延长,Ga掺杂量降低,ZnO薄膜的晶粒尺寸均一性变差,紫外光与可见光强度比减小.
ZnO has a wide direct band gap of 3.37 eV and a large exciton binding energy of 60 meV at room temperature, which is recognized as one of the promising semiconductors for optoelectronic device applications. However, ZnO generally displays visible defect-related deep-level emission and/or UV near-band-edge emission, which is strongly dependent on the growth method and condition. It has been reported that doping with IIIA elements can improve the optical properties of ZnO. Among them, Ga doping is considered not to induce large lattice distortion of ZnO due to the fact that the bonding lengths of Ga--O and Zn--O are similar and ionic radii of Ga3＋ and Zn2＋ are also similar. The gallium related compounds such as triethylgallium, gallium nitrate and gallium oxide are used as the Ga doping sources. It has been proved that ZnO film can be grown directly by the thermal oxidation of ZnS substrate. In this research, the Ga doping is adopted in the growth of ZnO film by applying the molten gallium to the surface of ZnS substrate and performing the subsequent thermal oxidation in the air at 650 and 700 ~C for 3 and 8 h, respectively. The effects of growth condition on the microstructures and photoluminescence properties of the Ga-doped ZnO film are investigated by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, and photoluminescence at room temperature. In addition, the relationship among the oxidation temperature, oxidation time, Ga doping content and photoluminescence properties is discussed. The results show that the Ga-doped ZnO films grown under different growth conditions exhibit various amounts of Ga content and the gallium is present in the ZnO matrix as Ga3＋ by partially substituting Zn2＋. The Ga doping affects the microstructure and photoluminescence property by changing the defect type and level, stoichiometric ratio, and crystal quality of ZnO film. As the oxidation temperature increases, the amount of Ga doping content increases. In addition, the grain size of the Ga-d
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2015年第8期332-338,共7页
Acta Physica Sinica
基金
国家自然科学基金(批准号:51202191)
陕西省自然科学基础研究计划(批准号:2012JQ6002)
陕西省教育厅科研计划(批准号:12JK0427)资助的课题~~
关键词
ZNO薄膜
Ga掺杂
热氧化
光致发光
ZnO film, Ga doping, thermal oxidation, photoluminescence
