Suppose the heavily doped p-GaAs described above is now sandwiched between AlAs barrier layers to form a single quantum well (SQW) structure with a well width, L_z = 100mL z  =100nm. Once again assume for simplicity that the quasi-Fermi level for holes is degenerate with the lowest possible energy level for holes and that the hole concentration is not significantly affected by optical pumping. By considering only the lowest quantized energy level for electron and ignoring any higher energy levels, calculate the minimum photo-generated electron concentration for net stimulated emission by using the 2D density of states for an SQW with L_z = 100: nmL z  =100nm. Give your answer in unit of cm^{-3}cm −3 . Answers within 5% error will be considered correct. Hint: For complete discussion on the density of states, see the lecture on Density of States in the Semiconductor Physics course (Module 2 Video 1). A portion of the video is posted below. The discussion on 2D density of states begins at ~9:16.