GATE EC 2022: Electronic Devices Quiz 9

The built-in-potential profile in the depletion region of a p-n junction in equilibrium is shown in the figure. The depletion region width is 1 μm.

Which of the following statements is/are true?

In a silicon p–n junction, the variation of the hole concentration in the space charge region is shown in the figure below, where the hole concentration changes from P_PO to P_no aver the space charge layer width

The hole diffusion constant in the space charge region is 6.5 cm²/sec. Then the hole diffusion current density J_P is _______ kA/cm².
(Note: Depletion width in the p–side, x_p = 1 and in the n–side, x_n = 2 )

At temperature T = 300 K, an n-type silicon contains donor concentration, N_D = 10¹⁴ cm^–3 and intrinsic carrier concentration ղ_i = 1.5 × 10^–10 cm^–3. Assume minority carrier lifetime of holes is _po = 10 μsec. Then lifetime of majority carrier electron is _____.

In an n–type semiconductor, the electron concentration (n_o) = 10¹⁵ cm^–3 and the intrinsic carrier concentration (n_i) is 10¹⁰ cm^–3. The mean life time of minority carriers is 10^–6 sec. The steady state excess hole concentration due to constant light illumination is d_{p = 4 × 10}⁵ cm^–3. The steady state electron – hole recombination rate is __________.

The parameters in the base region of an npn bipolar transistor are D_n = 20 cm²/s, n_B0 = 10⁴ cm^-3, x_B = 1 μm, A_BE = 10^-4 cm². What will be the collector current (in μA) for VBE = 0.5 V?