Research On Ag-doped ZnO Samples By Laser Induction

As one of the third-generation semiconductor materials,ZnO has many advantages,such as large energy gap,high exciton binding energy,chemical stability,toxic-free,low cost and so on,and is widely applied in the many fields,such as LEDs,LD,solar cell and piezoelectric devices.As a highly anticipated photoelectric material,some shortcomings of ZnO limit its application.Influenced by the point defects,the intrinsic ZnO shows the n-type characteristics.Due to the influence of the solid solubility and deep energy level,it is still a major challenge to prepare the high-quality p-type ZnO as well as homogeneous PN junction.The heteroepitaxial growth of ZnO becomes a common strategy.However,there exist someissues such as the lattice mismatch,thermal expansion coefficient difference and so on,which also largely hinders the further application of ZnO.Doping is an popular option for both preparing p-type ZnO according to the device standard and for obtaining the ZnO film with desirable performance.In this work,we used the doping method by laser induction.Doping elements are injected into the ZnO single crystal by the transient effect of laser high energy.Characterizations are then conducted,including X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),Raman scattering(Raman),and photoluminescence(PL).The first section of the experiment verifies the possibility of Ag doping by laserinduced.The Ag element added into the sample exists in the form of the substitution atom and metallic substance;the atomic radius of Ag is largen than that of Zn.Substituting Zn with Ag will enlarge the lattice constant and cause tensile stress and lattice damage.Due to the compensation energy level,the exciton emission peaks of the doped sample appear redshift;especially,there are two sharp emission peaks at 544nm and 612nm.To remove the lattice damage,the tensile stress of the sample is successfully released by rapid heat annealing treatment.the intensity of the sharp luminous peak caused by doping is weakened,and the crystallization quality of the sample is increased.The second section of the experiment mainly aims to explore the effect of laser power on the properties of the doped samples.It is found that the Ag content added in the sample and tensile stress of the sample increase with the increase of the laser power.The increases of Ag content result in the decrease of the peak intensity of ultraviolet band edge luminescence and blue-shift of the peak position,which is caused by the electron-hole pair effect.The sharp luminous peak mentioned above appeared in the sample prepared by lower laser power,and its intensity decreased with the increase of laser power.This work demonstrated the feasibility of the innovative strategy of laser-induced doping.In the future,more research will be performed to explore the influence of other experimental factors on the properties of the doped samples.