Re: schottky diodes???
Every junction formed between a metal and a semiconductor will act as a diode. But the work function (forward drop or depletion region) is inversly proportional to the doping concentration of the semiconductor.
If the semiconductor is lightly doped, the width of the depletion region will be considerably wide enough to act as a p-n junction having low forward drop (than ordinary semiconductor-semiconductor junction)
If the semiconductor is highly doped, then the depletion region will be very thin and it will act just as a continuation of the metal, forming an ohmic contact. (A contact is called ohmic when it obeys ohm's law perfectly)
Hence in ordinary diodes where metal-semiconductor junction is made only for making electrical contacts use highly doped semiconductor whereas in schottky diodes, it is necessary that the semiconductor region should be doped lightly.