Study Of Growth And Properties Of (Ga,Mn)N Films Grown On Sapphire And Quartz Substrate

As Diluted Magnetic Semiconductors(DMS) can make use of its electronic charge and spin properties simultaneously,it can be wide used in a new generation of optoelectronic devices,sensors,quantum computing,quantum communication devices,and so on.In particular,(Ga,Mn)N attracts the most attention for the Cruie Temperature beyond the room temperature and its background material GaN can obtain the widespread application in high temperature and high efficiency photoelectric device area.Besides,(Ga,Mn)N shows great potential on solar cells,Mn-doped can bring intermeditate band which could improve the efficiency of solar cells greatly.The experiments were carried out on the Electron Cyclotron Resonance-Plasma Enhanced Metal Organic Chemistry Vapor Deposition(ECR-PEMOCVD) system equipped with Reflection High Energy Electron Diffraction(RHEED) in situ.(Ga,Mn)N films were grown on the sapphire(a-Al₂O₃) and quartz substrate respectively.And using Cp₂Mn as Mn source,TEGa or TMGa as Ga sources.The crystal structure and surface topography of the(Ga,Mn)N films were characterized by RHEED,x-ray diffraction(XRD) and atomic force microscope(AFM).Optical property was characterized by photoluminescence(PL) spectrum.And the magnetism character of the films was investigated by superconducting quantum interference device(SQUID)(Ga,Mn)N film with Mn concentration up to 3%grown on a-Al₂O₃ substrate exhibited high(0002) preferred orientation and retained good wurtzite structure,no second phase was detected.The surface topography of(Ga,Mn)N film was composed of many submicron grains piled in the consistent orientation.SQUID test result showed that the films exhibited ferromagnetic at room temperature,no superparamagnetic or spin glass was detected.The Curie temperature of the films was about 400K.A shallow Mn acceptor level with bond energy of 453meV was found by room temperature PL spectra.(Ga,Mn)N films grown on quartz substrate contained less Mn concentration in contrast to those grown on a-Al₂O₃ substrate.Appropriate TMGa flux,relatively,lower growth temperature and smaller N₂ flux can increase the Mn concentration.All the films were polycrystalline,but exhibited some good(0002) preferred orientation.Mn₃Ga was detected in some films.Room temperature PL spectrum showed a near band emission peak concomitant with a Mn-related peak around 2.51eV in the low Mn concentration film,but with the increase of Mn concentration,the near band emission peak disappeared,and another Mn-related emission peak around 2.97eV appeared.Mn played an acceptor role in the films. (Ga,Mn)N films exhibited antiferromagnetic at room temperature.