Thursday, June 25, 2009

Field Emission Cathodes and modelling




While surfing the internet and searching some journals from the local library databases, I came across the above picture. I can't remember where I got it from.

Basically, it is a array of Field Emission cathodes. You can see it with your naked eyes. It is typically quite small (microns or nm).

Notice the shape of the individual cathodes are very much like pencil or permanent markers or even some candles. If we consider only one such cathode and consider the tip, it would like similar like this model:





Well, you can say that the model (second picture) does not look the same as that the first picture, but if you decrease the width of the FE cathode, the resulting model would look similar to the model.

Looking at the model, it is plotted in x-y coordinates or simply y is a function of x,
y =f(x), where x is a complicated equation and I don't want to put it here.

Since we know the relationship between y and x, how can we make it sharper or as sharp as possible at the tip of the cathode?


- wong chee tat :)