The band gap for the elemental semiconductor silicon is 1.11 eV. That energy corresponds to what wavelength and region of the electromagnetic spectrum? (1eV = 1.602 x 10-19J; 1 nm = 1 x 10-9)   1.778 x 10E(-19) J; Ultra-violet 1117 nm; Ultra-violet 1.117 x 10E(-6) nm; Infrared 1117 nm; Infrared

Explain how doping can increase the conductivity of a semiconductor.

8. Intensity (relative) 40.0 50.0 60.0 70.0 Diffraction angle 20 80.0 Figure 3.25 shows the first four peaks of the x-ray diffraction pattern for copper, which has an FCC crystal structure; monochromatic x-radiation having a wavelength of 0.1542 nm was used. (a) Index (i.e., give h, k, and / indices for) each of these peaks. (b) Determine the interplanar spacing for each of the peaks. (c) For each peak, determine the atomic ra- dius for Cu and compare these with the value presented in Table 3.1. 90.0 Figure 3.25 Diffraction pattern for polycrystalline copper.