# Homework Help: PNP Biploar Junction Transistor Energy Band Diagram

1. Oct 18, 2007

### l46kok

1. The problem statement, all variables and given/known data
Consider a PNP Biploar Junction Transistor uniformly doped in each region. Sketch the enegy ban ddiagram for the case when the transistor is biased in

a)In thermal equilibrium
b)biased in the active region
c)biased in the cutoff (depletion) region

2. Relevant equations
None, this is a problem asked to sketch (To an approximate scale) the energy band diagram.

3. The attempt at a solution

I've sketched the first two, but neither my book or the notes contained an example of a PNP Bipolar Junction Transistor's energy band diagram at a cutoff region. can anyone show me a site or include a diagram of this?

2. Nov 18, 2014

I registered here specifically because I wanted an answer to this and couldn't find it--until I stumbled on http://www.ece.umn.edu/academics/students/graduate/documents/prelims/Fall_2006/Fall%202006%20-%20Semiconductor%20Devices.pdf [Broken] PDF. For anyone else who googles this question and comes across this answer--you're welcome.

Backups in case PDF goes down: imgur tinypic postimage pasteboard

Text description: it's a mirror image of the PNP active diagram. There's a small hill at first and then a steep drop until it levels off.

ASCII representation (imagine @ as spaces):

@ -
- @@-
@@@ -
@@@@ - - - -

Last edited by a moderator: May 7, 2017