| In this work, we make a detailed investigation on the topic improving field emission current density, lowering the threshold field through film thickness, surface and structural modulation. On one hand, the work can promote the application of Vacuum Microelectronic devices through optimizing the device structure; on the other hand, understand physical mechanism and rules of field emission better.The influence of film thickness on AlxGa1-xN(for example GaN) field emission properties has been studied. Results show that field emission properties of 5nm ultrathin film are very excellent, the turn-on field is only 0.78V/μm(which is the lowest value of GaN film reported). there is an optimal film thickness value which has the best field emission performance for general film. The influence of film thickness on field emission is possible within the space charge density, effective barrier area and electron scattering.The influence of surface treating on AlxGa1-xN(for example AlN) field emission properties has been studied. The roughness of film increases from 1.0nm to 2.4nm after H plasma treating, but for the current density 0.1μA/cm2, the required field increases from 45V/μm to 71.4 V/μm, field emission properties reduced. H plasma treating can saturate the dangling bonds, reduce the defect density, leads the defect band reduced. Therefore weak the supply function, lower the field emission properties.The influence of structure modulation on field emission properties was studied. Thickness modulation on AlN/GaN was studied first, the turn on field of AlN/GaN is about 1/10 of single layer AlN, GaN, which shows that AlN/GaN was more superiority than single layer film on field emission. A little work was done on composition modulation of AlxGa1-xN. Al0.3Ga0.7N target and films were prepared, the test shows that its field emission properties are very excellent.
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