Interfacial atomic structure and band offsets at semiconductor heterojunctions

Abstract

The relationship between interfacial atomic structure and band offsets at semiconductor heterojunctions is explored through first-principles local density functional calculations. In particular, the effects of variations in interfacial geometry are analyzed for (001) interfaces between II I-V /III-V materials. For the AC/BC case of a common atom, isovalent A-B intermixing in the noncommon atomic planes near the interface does not affect the band offset, even in the case of large lattice-mismatched systems. For quaternary AB/CD systems, there are two possible chemically abrupt interfaces (A-D or B-C); these can have offsets that differ by up to 80 meV. In those cases where the chemically abrupt AB/CD offset depends on the interfacial identity, intermixing leads to offset variations which are directly related to the offset difference between the chemically abrupt AD and B-C interfaces. The differing behavior of common-atom versus non common-atom systems is analyzed in terms of the symmetry of the nearest-neighbor environment surrounding an atomic site of a composition change.

Quadratic response theory for spin-orbit coupling in semiconductor heterostructures

“…However, numerical evidence to the contrary was subsequently provided by Dandrea, Duke, and Zunger in a first-principles study of band offsets in InAs/ GaSb superlattices. 95 They deduced that the calculated difference between the macroscopic interface dipoles for InSb and GaAs interfaces must be a nonlinear effect ͑because such differences do not exist in linear response theory 51 in cubic crystals͒, but did not inquire further into its origin.…”

“…The magnitude of such dipoles is small-contributing 50 to 100 meV to the band offset of typical no-common-atom heterojunctions 95,102 -but they play an important role in explaining the experimentally observed asymmetry of band offsets in such systems. 102 As a final note, it is worth drawing attention to a fundamental property of the nonlinear response of insulators that apparently is not widely known.…”

“…͑This property of the nonlinear response was deduced from numerical calculations of band offsets in Ref. 95.͒ Furthermore, the quadrupole term n ␣␤ ͑2͒ − 1 3 n ͑2͒ ␦ ␣␤ is nonvanishing for any diatomic perturbation, since isotropy requires cubic symmetry.…”

Generalization of the effective mass method for semiconductor structures with atomically sharp heterojunctions

“…All these parameters determine the heterointerface contribution to the potential energy. At the same time, it is well known [34], that as a consequence of the possible appearance of an electric dipole moment at the interface of two materials the magnitude of the potential jump at the interface can also depend on the microscopic structure of the boundary. This is not described in our model of a heterojunction because we do not take into account the effect of such a dipole.…”

Influence of growth direction and strain conditions on the band lineup at GaSb/InSb and InAs/InSb interfaces

“…Finally, we neglect interdiffusion processes which lead to interfacial composition changes (i.e. we consider an atomically abrupt geometry) and relaxations at the interface of the anion-cation distance (bulk bond length away from the interface are considered equal to those immediately next to it): this, in fact, is expected [4,15,16] to introduce little modification of the charge rearrangement at the junction and hence of the VBO.…”