Affiliation: | a Faculty of Science, Physics Department, Sana'a University, Sana'a, Yemen b Physics Department, The University of Texas at Dallas, Richardson, TX 75083-0688, USA |
Abstract: | The E1 and E1+Δ1 energy bands of metal–organic chemical vapor deposition grown AlxGa1?xAs, with x in the range 0–0.55, have been determined using photoreflectance technique. The aluminum composition for each sample was determined using the energy of the room-temperature photoluminescence compensated peak value and a suitable fundamental band gap formula. The positions of the E1 and E1+Δ1 peaks were determined from curve-fitting an appropriate theoretical model to our experimental data by a modified downhill simplex method. Using the results, we propose new E1 and E1+Δ1 cubic expressions as functions of the aluminum composition, x, and compare them with the available reported expressions. |