Question

Hi I need help with question 3 shown below. Thank you

3) The p-n junction of problem 2 has a cross sectional area of 103 cm2. Calculate: a) the total depletion zone width, b)n-side depletion zone width, c) p-side depletion zone width, d) total charge on the n side, e) total charge on the p side and f) the peak electric field magnitude. g) Sketch εχ vs. x and the charge density to scale across the depletion zone as in Fig. 3-6.

This problem references problem 2, which I have already completed

Answer 1

a) Total depletion zone width W = squareroot 2t v_b/e N_a + N_d/N_a N_d = x_n + x_p N_a = doping concentration on p side = 10^15 cm^- 3 10^21 m^- 3 N_d = doping concentration on n side = 10^17 cm^- 3 = 10^23 m^- 3 v_b = build - in - potential = KT/e ln N_a N_d/n_i^2 = 1.38 times 10^- 23 times 300/1.6 times 10^- 19 ln 10^21 times 10^23/(1.5 times 10^16)^2 = 0.69 V therefore w = squareroot 2 times 11.7 times 8.85 times 10^- 12/1.6 times 10^- 19 times 10^21 + 10^23/(10^21 times 10^23) m [dielectric constant (si) = 11.7] w = 1.14 mm b) Let depletion width in n - region is x_n x_n/w = N_a/N_a + N_d x_n = w N_a/N_a + N_d = 1.14 times 10^21/(10^21 + 10^23) mm x_n = 0.011 mm c) Depletion width in p-region x_p = w times N_d/N_a + N_d = 1.14 times 10^23/(10^21 + 10^23) mm