【摘要】 考虑到薄膜中的电子散射,发展与完善了现有的场发射F-N(Fowler-Nordheim)模型,理论研究了不同厚度的半导体薄膜对其场发射性能的影响。结果表明:薄膜厚度对场发射性能的影响是非常显著的,随着薄膜厚度的增加,将相继出现极差膜厚值与最佳膜厚值,理论计算很好地验证了已有的实验结果;并进一步理论分析了半导体薄膜场发射性能随膜厚变化行为的物理实质,其可能来源于有效隧穿势垒面积的改变及电流密度在薄膜中的散射衰减。更多还原

【Abstract】 Recently, on the experiments, the characteristic of field electron emission of different novel semiconductor films and a variety of experimental methods to prepare semiconductor films have been paid more attentions. However, on the theories, there are rarely the related new reports. The main reason is that the traditional theories of field electron emission have not been adapted well to the novel nanomaterials which show different characteristics from the general semiconductor materials. So, it is necessary to set up a theoretical model to resolve the problem preliminarily. In the paper, by developing and improving conventional Fowler-Nordheim (F-N) field emission model considering electron scattering when electron transmits through the semiconductor film, the effect of thin-film thickness on field electron emission under the influence of an applied electric field has been studied theoretically. Barriers restricting electron transmission have an obviously change with the variation of the thickness of semiconductor film materials, so the current density of field electron emission also changed due to the variation of transmissive electron numbers. Results show that it is prominent for the effect of the film thickness on field electron emission. With the increase of the film thickness, there appears a worst film thickness value and an optimal film thickness value later for properties of field electron emission, which agreed well with some experimental reports. Correspond with this, the turn-on electric field appears a maximum and a minimum one after the other, however, the field electron emission current appears a minimum and a maximum one after the other. Furthermore, by analyses, distinct effects of the semiconductor film thickness on field electron emission may originate from the change of the area of effective tunneling barrier and the attenuation of electron scattering. Based on the model, not only some experimental results can be interpreted well, but also it can offer a theoretical guidance to the design of some vacuum microelectronic devices.更多还原