Electronic Devi...

Two GaAs wafers, one n-type and one p-type are uniformly doped such that N_D (wafer 1) = N_A (wafer 2) ≫ n_i. Which wafer will exhibit the larger resistivity?

A DC voltage of 10 V is applied across on n-type silicon bar having a rectangular cross-section and length 1 cm. Electric field developed in length is given by \(E = \frac{V}{l}\), and mobility of electron is \(1000\frac{{c{m^2}}}{{V - sec}}\). If the time taken by the electron to move from 0 to 0.75 cm is t₁ and time to move from 0.75 cm to 1.00 cm is t₂ then \(\frac{{{t_1}}}{{{t_2}}}\) is

Hole mobility in Ge at room temperature is 1900 cm²/V-sec. The diffusion coefficient is ________cm²/sec.

(Take kT/q = 25 mV)

Consider a sample of silicon doped with 2 × 10¹⁶ cm^-3 Boron atoms. Assume μ_n = 1300 cm²/Vsec, μ_p = 500 cm²/Vsec, n_i = 1.5 × 10¹⁰ cm^-3 and q = 1.6 × 10^-19 C. The electric field required in the sample to induce a drift current density of J = 120 A/cm² is:

An n-types GaAs semiconductor is doped with N_d = 10¹⁶ cm^-3 and N_a = 0 at T = 300 K. The electron mobility is 8500 cm²/V-sec and hole mobility is 400 cm²/V-sec for GaAs. The minority carrier lifetime is τ_p0 = 2 × 10^-7 sec. If a uniform generation rate g’ = 2 × 10²¹ cm^-3 sec^-1 is incident on the semiconductor, then the steady state increase in conductivity will be _______ (Ω – cm)^-1. 

At T = 300 K, an n-type silicon sample contains a donor concentration N_d = 10¹⁶ cm^-3 and intrinsic concentration n_i = 1.5 × 10¹⁰ cm^-3. The minority carrier hole lifetime is found to be τ_p0 = 20 μ sec.

What will be the lifetime of the majority carrier electrons?

Consider a semiconductor in thermal equilibrium (no current). Assume that the donor concentration varies exponentially as N_d(x) = N_d0 exp (-αx) over the range 0 ≤ x ≤ 1/α ; where N_d0 is a constant.