退火气氛对Zn0.87Co0.10Na0.03O薄膜光、电和磁性能的影响

Influence of Annealing Atmosphere on Optical,Electric and Magnetic Properties of Zn_(0.87)Co_(0.10)Na_(0.03)O Films

采用溶胶–凝胶法,在不同气氛下退火制备了Co和Na共掺杂的ZnO稀磁性半导体Zn0.87Co0.10Na0.03O薄膜,并试图通过共掺Na来实现ZnO基稀磁半导体的p型转变,测试了薄膜样品的结构、发光性能、电性能和磁性能。研究了退火气氛对样品性能的影响。结果表明:样品具有ZnO的纤锌矿结构,且表现出明显的c轴(002)择优取向特征,未检测到与Co和Na有关的衍射峰。在室温,340 nm波长激发下,样品在379～387 nm附近出现了1个窄的紫外发射谱带;在可见光区出现了1个宽的发射谱带(450～600 nm)。共掺Na未能实现样品的p型转变;样品的电子载流子浓度随退火气氛中氧气流量的减小而降低。富氧退火条件下获得的样品具有明显的室温铁磁性,其饱和磁化强度随氧气流量的减小急剧下降;而缺氧退火条件下获得的样品的铁磁性消失,出现反铁磁性。

Co-Na co-doped ZnO diluted magnetic semiconductor Zn0.87Co0.10Na0.03O films were prepared by sol–gel method and an-nealing in different atmospheres.The crystal structure,luminescence,electric and magnetic properties of the Zn0.87Co0.10Na0.03O film samples were determined,and the effects of annealing atmosphere on properties of the Zn0.87Co0.10Na0.03O film samples were investi-gated.The results show that the samples are ZnO wurtzite structure,and are preferentially oriented in the c-axis（002） direction,without finding any additional diffraction peaks related to Co and Na element.At room temperature,with excitation wavelength of 340 nm,there is a narrow ultraviolet emission band of around 379–387 nm and a wide emission band around 450–600 nm in the visi-ble light area.Na doped-ZnO does not obtain p-type ZnO.The electron carrier concentrations of n-type Zn0.87Co0.10Na0.03O films de-crease with the decrease of oxygen flux.The samples annealed in rich oxygen atmosphere have ferromagnetism at room temperature,and the saturation magnetization per unit volume of them sharply decreases with the decrease of oxygen flux.However,the samples annealed in hypoxic atmosphere are not ferromagnetism but anti-ferromagnetism.