The 'standard' Schottky diode contact is characterised by an ideality factor very close to unity: n = 1.0x, where 'x' is dictated by image force barrier lowering and interfacial dipole effects. In reality there is usually a very thin ( < 1nm) native oxide which pushes up the 'x' but it is still < 0.9.  Values of n> 1.1 can be explained by lateral surface inhomegeneity (see classic papers by R Tung). This may explain n up to 1.4 or so.  Larger n would require more thought and the pure thermionic emission is not valid; there may be a tunnelling component (thermionic field emission).  So a lot depends on the nature of the surface of the electrode at the nano-scale. A surface that is not  planar will possibly produce localised field intensification and related barrier lowering or tunnelling through the 'Schottky barrier'. Hope it helps.

I think, the current transport may be diffrent in case of nano-structures due to size dependent confinement issues and due to different techniques for nanostructure growth. But in your case the barrier height of order 10 is very doubtful. Are you using the general thermionic effect for the barrier height calculations?. You should also consider multiple gaussian distributions of barrier height at the junction and calculate the electrical parameters. You can follow my recent paper which is based on the same issue.

Article Temperature-dependent electrical characteristics of CBD/CBD ...

Thanks all for the very valuable answer and related materials you have shared.

To Avishek, yes I'm using the general thermionic effect for all calculations. Will surely consider the Gaussian distribution in my work too. Thanks for sharing your paper.

Dear @

The colleagues brought some explanations of the metal semiconductor contacts.

When you form metal -ZnO contact only by bringing the metal to the top of the nanowire: are you sure that they are intimately atom to atom contacted?

It is the device construction method that brings such big difference. You must build a real M-S contact on the atomic level. I think in your device you still have only very small contacted area compared to the whole area of the cross section of the nano wire. I would advise you to estimate the current density. Then you plot the current density versus the voltage. You can measure the capacitance of the device it will give you an estimation about the contact area with in fact much smaller than real cross section of the wire.

The barrier height can never be 10 times the theoretical value calculated from the energy level diagram.

The changes in the barrier height is caused by the interface sates or the inclusion of some insulating thin layers between metal and the semicondcutor.

Best wishes