Question

Would someone help me with A and B please

2) A voltage of 2 V is applied across the length of a 1 cm long Si bar doped with 1014 cm-3 of As with a cross sectional area of 0.02 cm2 and a temperature of 300 K. The bar is optically excited with a pulsed laser such that 102cm electron-hole pairs are generated per second uniformly in the sample when the laser is on. The electron recombination time is 2 μ s and the hole recombination time is 0.2 μs. a) Find the electron and hole concentrations in the sample when the laser is off. b) Find the electron and hole concentrations in the sample when the laser is on. c) Calculate the sample conductivities when the laser off and on. d) Calculate the current driven through the bar with the laser off and on. e) Find the equilibrium Fermi level with the laser off and compare this to the quasi-Fermi levels for electrons and holes when the laser is on. f Sketch these results together on an energy level diagram. holerbyFind theelectron and hole con Cikylate the current

Answer 1

given V = 2 v

L = 1 cm

N_d = 10¹⁴ / cm³

area = 0.02 m²

T = 300 K

generation rate is = 10²² / cm³

I_n = 2 us , I_p = 0.2 us

Given V = 2v L = 1 cm N_d = 10614/ cm^3 area = 0.02 m^2 T = 300 k generation rate is = 10^22/ cm^3 l_n = 2 us, l_p = 0.2 us (a) using solution for hole concentration = m^2/ N_D = (1.5 times 10^10)^2/ 10^14 = 2.25 times 10^6/ cm^3 (b) g = delta n/ 2n = delta P/ 2 p 10^22 = delta n/ 2 times 10^- 6 implies delta n = 2 times 10^16 /cm^3 = delta P n_z = 2 times 10^16 + 10^14 = 2.01 times 10^16/m^3 P_2 = 2.25 times 10^6 + 2 times 10^15 = 2 times 10^15/m^3 (c) sigma = 10^14 times 1.6 times 10^- 14 times 1300 sigma = 4.8 times 10^- 3 (d) R = sl/ A implies R = l/ sigma A = 1/ 4.8 times 10^- 3 times 0.02