【摘要】 用注射超声喷雾法将前驱体由针管直接送入超声喷头内,在石英基板上制备Zn_1-xCr_xO（x=0.0,0.01,0.03,0.05）薄膜。采用X射线衍射仪、扫描电子显微镜、荧光光谱仪、紫外-可见分光光度计、振动样品磁强计（VSM）等对薄膜的结构、光学和磁学性质进行测量。实验结果表明,未掺杂的ZnO薄膜为六角纤锌矿结构,沿着c轴（002）择优取向,而Cr掺杂抑制了薄膜的c轴择优取向性;掺杂后的薄膜平均晶粒尺寸均增大,且当x=3%时,晶粒尺寸最大,达31.4nm。扫描电镜（SEM）下薄膜呈球形颗粒状,并且在x=5%下,薄膜出现了长条状的微观形貌。Cr掺杂使样品的光致发光谱（PL）发生了很大的变化:未掺杂的样品的PL谱在378nm处存在一个紫外发射峰,对应于550nm附近还存在一个由于缺陷态引起的绿光发射峰;掺Cr样品只有在350⁵50nm的很宽的范围内存在一个发射峰,对其进行高斯拟合后,发现掺Cr量为x=1%,3%,5%下样品均存在V_Zn（锌空位）、Zn_i（Zn间隙位）、V_Zn^-（带一个电子的锌空位）内部缺陷态,且当x=3%时,V_Zn最多。Cr的掺杂使得薄膜的带隙增大,并且x=3%时,禁带宽度最大,达到3.374eV。掺Cr的三个样品均具有室温铁磁性,且x=3%样品的磁化强度最大,其与V_Zn（锌空位）最大相对应,验证了Cr³⁺和V_Zn的缺陷复合体是ZnO∶Cr样品具有稳定的铁磁有序的最有利条件的理论预测。更多还原

【Abstract】 The precursor solution is sent to the ultrasonic nozzle directly through a needle tube to prepare Zn_1-xCr_xO（x=0,0.01,0.03 and 0.05）films on quartz substratesby ultrasonic spray method.The structures,optical and magnetic properties of the films were measured by X-ray diffracmeter（XRD）,scanning electron microscope（SEM）,fluorescence spectrometer,ultraviolet-visible light detector,vibrating sample magnetometer（VSM）and so on.The experimental results indicate that,the undope dZnO thin films exhibit the hexagonal wurtzite crystalline structure with a preferential orientation of（002）;the Cr doping restrains the preferred orientation of C axis;the average grain sizes of the samples increase with Cr doping,and thesize attains the maximum（31.4nm）when x=3%.The SEMimages show that the Zn_1-xCr_xO（x=0,0.01,0.03 and 0.05）films are grain-like particles.And it exhibits a long strip shape when x=5%.Moreover,the doping of Cr makes the photoluminescence（PL）spectra of Zn_1-xCr_xO films change evidently.The undoped sample shows an ultraviolet emission peak at 378 nm as well as a defect related green peak at around 550 nm.However,for the doping samples,there is only a wide range of emission peak from 350to550 nm.By gaussian fitting,it is found that V_Zn,Zn_i and V_Zn^- defects exist in the Cr doping films,and V_Zn is largest when x=3%.The band gap increases with the doping of Cr,and reaches the maximum when x=3%.The doping of Cr hasthe band gap of the samples increase,and the band gapreachs themaximum（3.37eV）when x=3%.Magnetic measured results show that threedoping samples Zn_1-xCr_xO（x=1%,3% and 5%）are ferromagnetic at room temperature,and the magnetization of Zn_1-xCr_xO（x=3%）is the largest,which is corresponding to the most V_Zn defect.The experimental results also prove the the oretical prediction that the substitutive Cr in the oxidation state of +3 and the neutral Zn vacancy in the ZnO∶Cr sample are the most favorable defect complex to maintain a high stability of ferromagnetic order.更多还原