Structure,Morphology,Optical And Magnetic Properties Of Co?Ni-doped SnO Materials

SnO is a kind of multifunctional materials.On account of the excellent the optical and conductive properties,it has been applied to the solar and thin film transistors.Compared to other oxide semiconductor,SnO could be a better native p-type oxide semiconductor because of Sn 5s nature at the valence band maxima?VBM?,which might result in a more effective holes transport path and higher holes mobility.As a typical p-type wide band gap semiconductor,most studies on SnO were concentrated on the electrical and catalytic properties.In order to broaden its application,researchers try to introduce spin into SnO.In 2011 and in 2014,Tan et al.and M et al.respectively discovered the spin magnetic moment in cation doped SnO.However,the ferromagnetic origin of SnO is still disputable and it is necessary to explore further.Because of the special unit cell structure,it is easy to synthesize a variety of morphologies of SnO.Studies show that the morphology of SnO is important to its properties and applications.Therefore,in this paper,three sections were carried out.?1?Various morphologies SnO were successfully synthesized via hydrothermal process based on different reactive solvents?NH₃·H₂O and KOH solution?.With NH₃·H₂O solution,the precipitate present square plates and the content of deionized water in hydrothermal process affect the size of plates.However,the alkaline?KOH?solution make the precipitate grow into flower-like SnO consisting of various microsheets.The complicated structures more tend to generate surface defects.?2?The typical plate-like Sn_1-xCo_xO particles were synthesized by hydrothermal growth method.SEM and TEM results show that the obtained particles are consist of nanosheets with a thickness of¹0 nm.XRD and Raman spectra result show that the Co-doping has certain influence on the host lattice structure and Co would occupy different positions(Co_Sn and Co_i)with different doping concentrations.And the optical band gap of the samples firstly narrows and then widens as the positions of Co changing from substituted sites to interstitial sites.Meanwhile,room-temperature ferromagnetism originated from the double exchange interactions between the O 2p and Co 3d states is discovered as well,and the ferromagnetism firstly increases and then decreases with Co concentration increasing.?3?Sn_1-xNi_xO nanoflowers self-assembled with nanopetals have been synthesized successfully.Structure measurement results show that all the samples possess typical tetragonal structure and Ni would occupy different positions(Ni_Sn and Ni_i)with various concentrations.The bandgap of SnO tends to shrink firstly then widen after Ni-doping,which is caused by the sp-d exchange interactions and the Burstein-Moss effect.Meanwhile,PL and XPS measurements illustrate that tin vacancies(V_Sn)and oxygen vacancies?V_O?were generated during the process of preparation and the V_Snn as the origin of the ferromagnetism in pure SnO was verified by air-anneal experiment.In addition,Ni-doping can improve the ferromagnetism via enhancing the content of V_Sn.This literature studies the ferromagnetism of novel SnO flower-like structure firstly and reasonably reveals the desired ferromagnetism originated from the V_Sn.