In: Physics
10.
Consider a step pn junction made of silicon. Carrier lifetimes are given as \tau_n = 10^{-7} sτn=10−7s and \tau_p = 10^{-7} sτp=10−7s. Assume long diode, i.e. long quasi-neutral regions. What must be the doping density ratio, N_A/N_DNA/ND, in order to have 95% of the total current in the depletion region carried by electrons?
Answers within 5% error will be considered correct.
11.
Consider two ideal pn junctions at T = 300\: KT=300K with exactly the same physical parameters except for the bandgap energy. The first pn junction has a bandgap energy of 0.525 eV and a forward current of J_1 = 10\: mAJ1=10mA at V_a = 0.255\: VVa=0.255V. For the second pn junction, a forward current of J_2 = 10\: \mu AJ2=10μA was measured at V_a = 0.32\: VVa=0.32V. What is the bandgap energy of the second pn junction material?
Give your answer in unit of eVeV. Answers within 5% error will be considered correct.