金刚石颗粒与硅基底的超声焊接及场发射性能(英文)

Ultrasonic Weldingof Diamond Particles on Si Surface with the Field Emission

采用一种超声焊接工艺,通过施加纳米幅度的超声水平振动将金刚石颗粒牢固地焊接于硅基底表面。在此过程中超声力小于硅所能承受的剪切应力,使硅表面得以发生超声软化进而促成焊接的形成。焊接界面的分析结果表明硅与金刚石颗粒之间的连接不仅仅是机械嵌合,还包括原子之间的键合。当焊接时间为5 s、振幅为500 nm时形成了稳固的纳米焊接。焊接后的金刚石场发射阴极获得了较低的开启场强(电流密度为1μA/cm2时的场强)1.4 V/μm,并且当电场强度达到9.6 V/μm时,可获得到高达1 mA/cm2的电流密度。

The diamond particles were stably welded on the silicon substrate by applying a nanoscale horizontal vibration with a simple efficient ultrasonic welding process.The very small amplitude of the ultrasonic welding ensures that the force can not exceed the shear force of the silicon tolerance,and then the welding was formed by ultrasonic softening effects at the surface of silicon.The analysis results of the welding interface indicate that the connection between diamond particles and silicon substrate is by mechanical bonding and linkage between atoms.The robust nanowelding was formed for the welding time of 5 s and the amplitude of 500 nm.For the welded diamond particle cathodes,the low-threshold field（defined as the electric field at the emission current density of 1μA/cm^2）of 1.4 V/μm can be obtained,and the current density is1 mA/cm^2 under an applied field of 9.6 V/μm.