Semiconductor Physics: Fraction of Drift Current Flow Due to Electrons

[hogrampage]

Homework Statement

A certain doped semiconductor at room temperature has the following properties: n_o = 9 x 10¹⁴ / cm³, p_o = 4 x 10¹⁴ / cm³, μ_e = 800 cm² / V-s, μ_h = 400 cm² / V-s, and (D_h$\tau$_h)^1/2 = 10^-4 cm.

If an electric field is applied, what fraction of the resulting drift current flow will be due to electrons?

Homework Equations

Not sure.

The Attempt at a Solution

I have no idea what to do, but the answer is 0.82 (according to the book).

 

[AugustCrawl]

Could you perhaps state what you think all the letters mean?

I would guess that:
No is charge carrier density of n type
p is charge carrier density of p type
no idea what μ e and h are ... or what Dh and Tau h are,

In my experience (if this came from a lecturer) he will have given you a formula. Perhaps even with all these terms present.. and the answer may just fall out...

I found this related PDF
http://users.ece.gatech.edu/~alan/ECE3080/Lectures/ECE3080-L-7-Drift - Diffusion Chap 3 Pierret.pdf

It contains equations for calculating hole and drift currents (if you have the right parameters available).

Maybe if you worked out the hole current , worked out the drift current ... and divided one by the other to get the ratio?

Sorry its not a complete answer but it may get you going in the right direction :)