Question

E E EF E

The figure shows band diagram of a BJT structure
under bias.

a) Name the semiconductor types, biasing mode
(Plot base, emitter and collector and voltage polarities) and the
carrier types shown in figure (majority or minority). Plot
clearly BJT structure and charge flow.
b) If we connect two diodes to form pn-np or np-pn structure it
will not behave like a BJT transistor. Explain why (one or two
sentences).

Please help me , i dont have too much time

Answer 1

Here, we have pnp BJT such that Ec Р. - Ei EF Pt Ev n O Emitter Collector Base Forward Bias Reverse Bias ( a ) Semiconductor is php type where Emitter Base are forward bias & Base en collector are reverse bias. Thus, BJT is in active mode or act as an amplifier thus, majority carrier holes from emitter mores towards the base whereas majority carrier elections from base move to emitter. Now, base a collector are reverse biased thus, holes mo moving from base to collector are minority carriers. from similarly, electrons moving collector to base are minority.

two pn Junction because (b) If we connect diodes back to back Connected, then it would not work like a a BJT transistor in this Case n- region will be too thick so most the majority charge cassiers rushing from emitter to Collector will will be neutralized in the base. As a result, the transistor will not work. & of