PN Junction Diode Thermoelectric Generator?

Hi, I was wondering if you could DIY a thermoelectric generator by dissecting  some PN junction diodes and sandwiching the P type material adjacent to the N type materials between heat conductive material, such as two circuit board wafers?

I'm sure it could work. How would you dissect the diodes and put enough of them together to actually generate a usable amount of current?

It would be much easier and cheaper to just buy a Peltier cooler.
Diodes aren't made by joining two pieces of material together like that.