Daniel Mourad, Jan-Peter Richters, Lionel Gérard, Régis André, Joël Bleuse, Henri Mariette
We present a combined experimental and theoretical approach for the determination of the valence band offset (VBO) at CdSe/ZnTe heterojunctions with underlying zincblende crystal structure. On the experimental side, the optical transition of the type II interface allows for a precise measurement of the type II band gap. We show how the excitation-power dependent shift of this photoluminescence (PL) signal can be used for a precise determination of the VBO. On the theoretical side, we use a refined empirical tight-binding parametrization in order to accurately reproduce the band structure and density of states around the band gap region of cubic CdSe and ZnTe and then calculate the branch point energy (also known as charge neutrality level) for both materials. Because of the cubic crystal structure and the small lattice mismatch across the interface, the VBO for the material system under consideration can then be obtained from a charge neutrality condition, in good agreement with the PL measurements.
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http://arxiv.org/abs/1208.2188
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