Synchro-epitaxy is introduced and a “two periods epitaxy” process is proposed.The influence of the flows of SiH 4 N 1,N 2,deposition time t 1,t 2,and epitaxial temperature T on epilayer quality (embodied by α)...Synchro-epitaxy is introduced and a “two periods epitaxy” process is proposed.The influence of the flows of SiH 4 N 1,N 2,deposition time t 1,t 2,and epitaxial temperature T on epilayer quality (embodied by α) is reported.The shorter initial inducing time t 1 and larger flows of SiH 4 are,the wider single crystal strips are.But the quality of epilayer may be poor.The optimum conditions are:N 1=13.1～17.5sccm,N 2=7.0～7.88sccm,and t 1=30～50s.The influence of temperature is complex:when T is lower than 980℃,single crystal strips increase with T ;when T is higher than 980℃,single crystal strips decrease with T.It reaches maximum near 980℃.展开更多
Previous reports about the growth of large graphene single crystals on polycrystalline metal substrates usually adopted the strategy of suppressing the nucleation by lowering the concentration of the feedstock, which ...Previous reports about the growth of large graphene single crystals on polycrystalline metal substrates usually adopted the strategy of suppressing the nucleation by lowering the concentration of the feedstock, which greatly limited the rate of the nucleation and the sequent growth. The emerging liquid metal catalyst possesses the characteristic of quasi-atomically smooth surface with high diffusion rate. In principle, it should be a naturally ideal platform for the lowdensity nucleation and the fast growth of graphene. However,the rapid growth of large graphene single crystals on liquid metals has not received the due attention. In this paper, we firstly purposed the insight into the rapid growth of large graphene single crystals on liquid metals. We obtained the millimeter-size graphene single crystals on liquid Cu. The rich free-electrons in liquid Cu accelerate the nucleation, and the isotropic smooth surface greatly suppresses the nucleation.Moreover, the fast mass-transfer of carbon atoms due to the excellent fluidity of liquid Cu promotes the fast growth with a rate up to 79 μm s^-1. We hope the research on the growth speed of graphene on liquid Cu can enrich the recognition of the growth behavior of two-dimensional(2 D) materials on the liquid metal. We also believe that the liquid metal strategy for the rapid growth of graphene can be extended to various 2 D materials and thus promote their future applications in the photonics and electronics.展开更多
文摘Synchro-epitaxy is introduced and a “two periods epitaxy” process is proposed.The influence of the flows of SiH 4 N 1,N 2,deposition time t 1,t 2,and epitaxial temperature T on epilayer quality (embodied by α) is reported.The shorter initial inducing time t 1 and larger flows of SiH 4 are,the wider single crystal strips are.But the quality of epilayer may be poor.The optimum conditions are:N 1=13.1～17.5sccm,N 2=7.0～7.88sccm,and t 1=30～50s.The influence of temperature is complex:when T is lower than 980℃,single crystal strips increase with T ;when T is higher than 980℃,single crystal strips decrease with T.It reaches maximum near 980℃.
基金supported by the National Natural Science Foundation of China(21673161)the Sino-German Center for Research Promotion(1400)
文摘Previous reports about the growth of large graphene single crystals on polycrystalline metal substrates usually adopted the strategy of suppressing the nucleation by lowering the concentration of the feedstock, which greatly limited the rate of the nucleation and the sequent growth. The emerging liquid metal catalyst possesses the characteristic of quasi-atomically smooth surface with high diffusion rate. In principle, it should be a naturally ideal platform for the lowdensity nucleation and the fast growth of graphene. However,the rapid growth of large graphene single crystals on liquid metals has not received the due attention. In this paper, we firstly purposed the insight into the rapid growth of large graphene single crystals on liquid metals. We obtained the millimeter-size graphene single crystals on liquid Cu. The rich free-electrons in liquid Cu accelerate the nucleation, and the isotropic smooth surface greatly suppresses the nucleation.Moreover, the fast mass-transfer of carbon atoms due to the excellent fluidity of liquid Cu promotes the fast growth with a rate up to 79 μm s^-1. We hope the research on the growth speed of graphene on liquid Cu can enrich the recognition of the growth behavior of two-dimensional(2 D) materials on the liquid metal. We also believe that the liquid metal strategy for the rapid growth of graphene can be extended to various 2 D materials and thus promote their future applications in the photonics and electronics.
