The following questions are based on the band-diagrams of InAs and
GaAs (shown in Page 2). You ONLY need to use these graphs to
estimate any device parameters. Assume the electron affinities of
InAs to be 4.9eV and of GaAs to be 4.07eV. Use rulers/scale to
determine the energy levels and curvature.
1. Draw a simplified band-diagram corresponding to the two materials
and estimate the location of the Fermi-energy. Assume that the
Fermi-energy level is exactly at the mid-point of the band-gap. Note
that in practice this will not the case due to the difference in electron
and hole’s effective mass. [10 points].
2. Draw the band-diagram of a junction formed by the InAs and GaAs
material. What is the potential difference formed across the two
junctions [10 points].