GaAs微尖阵列的制备与场发射性能

Fabrication and Field Emission Property of GaAs Microtips Array by Selective Liquid Phase Epitaxy

利用选择液相外延的方法制备GaAs微尖阵列,通过扫描电子显微镜对微尖形貌进行了表征,并对此微尖阵列进行了场发射性能测试。结果表明,选择液相外延法制备的GaAs微尖呈金字塔状,两对面夹角为71°;微尖高度由生长窗口的尺寸决定,对底边为60μm的微尖,其高度约为42μm。此微尖阵列排列规则,具有场发射特性,开启电场约为5.1V/μm。发射电流稳定,当电场由8.0V/μm增加到11.9V/μm,发射电流由6μA增到74μA,在发射时间超过3h的情况下,电流波动不超过3%。另外,GaAs微尖阵列场发射的F-N曲线不为直线,分析表明是表面态和场渗透共同作用的结果。这对GaAs微尖阵列在场发射阴极方面的进一步研究具有重要的意义。

GaAs microtips array are fabricated by selective liquid phase epitaxy （LPE）. Scanning electron microscopy （SEM） images show that the microtip is pyramid-like with the angle of the opposite sides about 71° The height of the GaAs microtip is depended on the size of the growth window. In the experiment, the growth window of 60 μm× 60μm results in the microtip height of 42 μm. Furthermore, the field emission property of the tips array is also investigated. A turn-on field of 5.1 V/μm and a good current stabilityare obtained. The field emission current increases from 6 μA to 74 μA when the electric field changes from 8.0 V/μm to 11.9 V/Ixm. The current fluctuation is found not to exceed 3% over a period of 3 hours. Furthermore, the nonlinear field emission F-N curve of GaAs microtips array is also studied. The influence of the surface, states of electrons and the field penetration are considered to be the reason for the non-linear field emission F-N curve. This achievement reported here represents a significant step towards the application of GaAs microtips array as a field emission material.