1
$\begingroup$

I know the equation for intrinsic carrier density is $$ n_i = BT^{3/2}e^{-E_g/2kT} $$ Where B is a material dependent quantity. But how would you determine $n_i$ experimentally? Or if you were given an intrinsic semiconductor but no quantitative information about it, how would you go about finding $n_i$?

This is purely out of curiousity, so thanks for any help and suggestions!

$\endgroup$

1 Answer 1

2
$\begingroup$

There are several experimental methods to determine the intrinsic carrier concentration of a semiconductor. Most of them are indirect. For example you can measure the conductivity of the semiconductor at relatively high temperatures where it has intrinsic properties. Then you determine the electron and hole mobilities and obtain the intrinsic concentration from the conductivity. A second methods uses measurements of the densities of states of valence and conduction bands and of the band gap. Other methods use the characteristics of semiconductor devices. All these methods give errors in the range of several percent. A scientific paper which gives the most accurate recent results for silicon uses the injected minority carrier flow in a pn-diode. The abstract of the paper can be seen here http://scitation.aip.org/content/aip/journal/jap/70/2/10.1063/1.349645 (I don't know if you can also download it for free.) The references in this paper also describe other methods.

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.