The electrical contact nature between metal and semiconductor plays a key role in the devices operating and performance. An investigation of the contact ohmicity of different metals with p-NiO and n-ZnO semiconducting material is addressed in the present work. The investigated metals are the commonly used ones: Au, Cu, Mo, Ti, Ag, and indium tin oxide (ITO). All the studied metals lead to an ohmic contact with NiO and ZnO semiconductors expected in the case of ITO on NiO where the contact was rectifying. The formation of ohmic contact is explained in terms of the difference between the metal work function and the semiconductors affinity in one hand and on the other hand, in terms of highly doped interface formation due to the oxygen vacancies appearance, reducing then the depletion layer width which favors the carrier transport through tunneling effect. High sheet resistance is measured when using Ag metal as a contact on both ZnO and NiO, due to the diffusion of the latter in the film bulk and to the formation of Ag cluster. Mo, as well, leads to higher sheet resistance when used on NiO due to the metal diffusion. However, due to the conduction band gap offset at the interface ITO/NiO and ITO /ZnO, ITO leads to a Schottky contact with NiO and ohmic one with ZnO.

金属与半导体之间的电接触特性在器件的运行和性能中起着关键作用。本文研究了不同金属与p-NiO和n-ZnO半导体材料的接触电阻的研究。研究的金属是常用的金属：Au，Cu，Mo，Ti，Ag和铟锡氧化物（ITO）。所有研究的金属都会导致与NiO和ZnO半导体的欧姆接触，而在ITO在NiO上进行整流的情况下，这是所期望的。一方面根据金属功函数与半导体亲和力之间的差异来解释欧姆接触的形成，另一方面根据由于氧空位的出现而形成的高掺杂界面来​​解释欧姆接触的形成，然后减小耗尽层宽度，这有利于通过隧穿效应进行载流子传输。当将Ag金属用作ZnO和NiO的接触点时，由于后者在膜块中的扩散以及Ag团簇的形成，因此测量到较高的薄层电阻。当在NiO上使用Mo时，由于金属扩散，Mo也会导致较高的薄层电阻。但是，由于ITO / NiO和ITO / ZnO界面处的导带隙偏移，ITO导致与NiO的肖特基接触和与ZnO的欧姆接触。