Solid State Electronic Devices, 7th Edition

Problems

1. 8.1 For the p-​i-​n photodiode of Fig. 8–7, (a) explain why this detector does not have gain; (b) explain how making the device more sensitive to low light levels degrades its speed; (c) if this device is to be used to detect light with λ = 0.6 μm, what material would you use and what substrate would you grow it on?

2. 8.2 We make a quantum well by sandwiching a 60 Å layer of GaAs (E_g = 1.43 eV) between AlAs with a bandgap of 2.18 eV. We can assume two-​thirds of the bandgap difference appear as conduction band discontinuity, and the rest in the valence band. The electron and hole effective masses in GaAs are 0.067 m₀ and 0.5 m₀, respectively. If we make an LED out of this heterostructure, what is the lowest energy photon that can ...