equilibrium state of a diode

[p11]

A pn junction diode when gets into equilibrium then diffussion current becomes equal to the drift current .. am i right ? but how . because i think the electric field in the space charge region creates an energy barrier which stops the diffusion completely , is not it ... please explain in simple words ...

 

[mtwieg]

Diffusion currents always occurs according to fick's laws. An "energy barrier" doesn't negate this, but an electric field may establish a drift current which cancels out the diffusion current.

 

[p11]

we know that at equilibrium the drift current that flows is totally consisted of minority carriers . now when the junction is formed , the barrier potential opposes the diffusion current but the minority carriers (say electrons in p region) can anytime move from p to n region because electrons in p region are at higher energy state than n region and as electrons always try to move from high o low energy state so they can move from p to n region ??? is this logic correct ?