Answer to Question #251724 in Physics for Keahu

Question

Q1. A silicon wafer is 0.5 mm thick

(a) A potential of 100mV is applied across the thickness, what is the electron drift velocity if their mobility is 0.2m/V-s. (b) How much time is required for an electron to move across the thickness?

Answer 1

(a) The drift velocity is

$$v_d=\mu_eVd=(0.2·10^{-3})·0.1·0.0005=\\=10·10^{-9}\text{ m/s}.$$

(b) The time is

$$t=\frac d{v_d}=50000\text{ s, or 13 h 53 min}.$$