Diodes have a voltage difference across the junction.
It is measurable, and has been used for years as a bias voltage. You can put them in series and get higher voltages.
Some electronic chips use this as a keep alive memory voltage. (normal memory chips lose their information when the voltage is disconnected). Chips that have stacked diodes will keep their memory.
I take it they have stacked them in a wire to make the “nano wire”.
> Diodes have a voltage difference across the junction.
Oh man. Yes, but only when there’s a current ...
Diodes do not hold a charge or otherwise _store_ energy in any meaningful way.
Some photovoltaic devices are diodes, yes, but generating electricity is not something that all diodes do.