EFFECT OF TEMPERATURE ON THE MOBILITY AND CONDUCTIVITY OF ELECTRONS AND HOLES

The SI unit of electron mobility is :

In an intrinsic semiconductor the energy gap E_(g) is 1.2 eV . Its hole mobility is much smaller than electron mobility and independent of temperature. What is the ratio between conductivity at 600K and 300K ? Assume that temperature dependence intristic concentration n_(i) is given by n_(i)=n_(0) exp ((-E_(g))/(2k_T)) , where n_(0) is a constant and k_=8.62xx10^(-5)eV//K .

The mobility of electrons when compared tot hat of holes is

Assertion: Electron has higher mobility than hole in a semiconductor. Reason: Mass of electron is less than the mass of hole.

Determine the conductivity of pure germanium at 27^(@)C . The concentration of the carriers at this temperature is 2.2 xx 10^(19)m^(-3) . The mobility of electrons = 0.36 and that of holes = 0.17

Out of electron and hole, which one has highter mobility and Why?

Using the microscopic form of Ohm's law (J=sigma E) , prove that conductivity of a metal can be written as sigma="ne"mu . Here n is the number of free electrons per unit volume and mu is mobility of free electrons . In case of semiconductors there are two types of conduction particles, one is free electrons and the other is known as a hole. Charge on the hole may be assumed to be equal and opposite of that on electron. The number density of free electrons and holes in the semiconducting material are n and p respectively. Assuming mu_e and mu_h as mobility of free electrons and holes respectively , write the exopression of conductivity of the semiconducting material.

The effect of temperature increase on conduction as -