Question

An electric field is applied to a semiconductor. Let the number of charge carries be nand the average drift speed by v. If the temperature is increased,

Options

• both n and v will increase

• n will increase but v will decrease

•  v will increase but n will decrease

• both n and v will decrease.

Answer 1

n will increase but v will decrease

As we increase the temperature, additional electron‒hole pairs are created in a semiconductor. As a result, the number of charge carriers increases.
Now, drift velocity ( vd)  is given by

`vd =(-eEr)/m`
As the temperature increases, the relaxation time of charge carriers (T)  decreases. As a result, v_d decreases.