Collector Base Junction

This fig exhibits the Collector-base junction where collector is built up of P-type material and Base is made through N-type material. In fig +ve terminal of the battery is attached to Base whereas -ve terminal is attached to the Collector. It means this junction will go in reverse-biased mode and depletion layer will be broadened and the  current will flow because of minority carriers.

In fig given above +ve terminal of the battery is attached to Emitter whereas -ve terminal of V_EE is attached to the the Base whereas on the right side of this fig +ve terminal of the battery V_CC is attached to Base and -ve terminal is associated to the Collector. There are 2 depletion layers in fig in which one is small whereas the other is bit wider and this is because of the forward biased of emitter-base junction and reverse biased because of the collector-base junction. We also observe the emitter current I_E will flow inward that is pointing into the transistor, though the base current I_B  and collector current I_C is exhibited going outward from transistor.