Determination of the valence band offset at cubic CdSe/ZnTe type II heterojunctions: A combined experimental and theoretical approach

Abstract

We present a combined experimental and theoretical approach for the determination of the low-temperature 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 any type II system 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.

11 pages, 5 figures

References in corpus (4)

• Aharanov-Bohm excitons at elevated temperatures in type-II ZnTe/ZnSe quantum dots
• Optical Aharonov-Bohm effect in stacked type-II quantum dots
• A comparison of atomistic and continuum theoretical approaches to determine electronic properties of GaN/AlN quantum dots
• Theory of band gap bowing of disordered substitutional II-VI and III-V semiconductor alloys

Cited by in corpus (5)

• Strain Influence on Optical Absorption of Giant Semiconductor Colloidal Quantum Dots
• Tight-binding branch-point energies and band offsets for cubic InN, GaN, AlN and AlGaN alloys
• Optical Determination of the Band Gap and Band Tail of Epitaxial Ag${}_2$ZnSnSe${}_4$ at Low Temperature
• Excitonic fine structure of epitaxial Cd(Se,Te) on ZnTe type-II quantum dots
• Near-infrared emission from spatially indirect excitons in type II ZnTe/CdSe/(Zn,Mg)Te core/double-shell nanowires