What Are Heavy Holes, Light Holes, and Split Off Holes in Semiconductors?

[ehrenfest]

Homework Statement

A hole is just a valence band with one missing electron. A semiconductor is just a material that has its conduction electron concentration within a certain range. A direct-gap semiconductor is just a semiconductor with the conduction band edge and the valence band edge on the same vertical in the k-E graph.

But then my book talks about heavy holes and light holes and split off holes and I just don't understand what they are.

Homework Equations

The Attempt at a Solution

 

[tiny-tim]

Does this help?

http://touch.caltech.edu/courses/EE40%20Web%20Files/Supplements/01_Effective_Mass.pdf​

 

[ehrenfest]

Does this help?

http://touch.caltech.edu/courses/EE40%20Web%20Files/Supplements/01_Effective_Mass.pdf​

Sorry, not really. I just don't understand what they are. I don't understand how you can have three different valence bands when I thought by definition there was only one?

 

[ehrenfest]

anyone?

SOMEONE PLEASE HELP! I NEED TO UNDERSTAND THIS! What is a heavy hole and what is a light hole?

 

[ehrenfest]

Help!