- #1

Kara386

- 208

- 2

## Homework Statement

How many free electrons are there in the CB? Diamond has a bandgap of ##5.5##eV.Assume the material is at room temperature and that there are ##2 \times 10^{22}## cm##^{-3}## electrons in the material. What does this mean for their use in semiconductor devices?

## Homework Equations

## The Attempt at a Solution

Probably I should use something like this equation:

##n = N_c \exp\left(\frac{E_F - E_C}{kT}\right)##

Where ##N_c = \frac{8\pi\sqrt{2}m^{*3/2}}{h^3}\sqrt{E-E_c} ## is the effective density of states, and then multiply by the number of electrons in the material cm##^{-3}##. But there's quantities in there I don't know and can't calculate, like the Fermi energy (although is that half the gap?), and the energy of the conduction band, and the effective mass. I feel like this should be a simple question, but I can't see how to do it. It's possible, although unlikely, that I just have to look these quantities up, but if there's any other way I'd rather not do that. Thanks for any help! :)