Question

SOLAR CELLS! I understand how a forward bias reaction occurs, i'm just curious how we actually harness the energy? do we make a closed circuit with a resistor? orrr what

Answer 1

In solar cells, there is no biasing at all. you treat the pn junction itself as a battery. The way is works in principle is pretty simple, when light falls on the depletion region, electron hole pairs are created,

These electrons can now drift across the diode (because of the E field generated at the depletion region) and this diffusion current (which is quite small) is the one that flows through the load, and powers up the load.
since this is the drift current, its negative (according to the sign convention)
and the potential difference across the diode becomes positive .. so the VI characteristics of this comes in the fourth quadrant!