Question

Generation and Recombination: Determine the mobility of a hole that can travel a distance ofAx and an electrical field of 125 V/cm. 0.125 cm in a time ofAt = 10-6 sec What happens to the carrier concentration, with respect to time, when G- R? Draw an energy band diagram showing carrier generation using light. Tp is called the "RC time constant" in this formula: τ, True or False no For indirect-bandgap semiconductors, such as silicon, a direct recombination process is very likely True or False For indirect-bandgap semiconductors, such as silicon, a direct recombination process is very likely True or False The Auger process involves three particles. True or False Continuity Equation:

Answer 1

"Mobility(mu) = Vertical-bar v_d/elipsion Vertical-bar = (delta x/delta t)/epsilon = (0.125 cm/10^-6 sec/125 v/cm mu = 1000 cm^2/V - s 2) when G = R, i.e. Rate of generation becomes equal to rate of recombination, the concentration of electrons and holes becomes constant 3) when light falls, the electrons in valence band get energy and move to conduction band creating e - h pair smallest energy required = epsilon_g = epsilon_c - epsilon_v \r\n tau_p = 1/beta n_n_0 is caused life time of holes. which given average time for which hole can be in excited state before suffering recombination. Hence given statement is 'false' 5) False, indirect band gap semiconductor are characterized by indirect recombination. First loose momentum then energy which is very unlikely auger process is the process in which a vacancy is created by high energy e^-. This vacancy is filled by downward transition of electron in atom the photon released may cause another electron to be ejected from atom. This is caused auger electron. Hence total three particles are involved. So statement is ""True""."