Ambiguity in the magnitude and direction of the derived interface dipole in lanthanum aluminate heterostructures: Implications and proposed solution

作者：Liu Z Q; Chim W K^*; Chiam S Y; Pan J S; Ng C M

来源：Journal of Applied Physics, 2011, 109(9): 093701.

DOI：10.1063/1.3579423

The electric field strength of interface dipoles cannot be measured directly but can be derived from measurable electronic properties such as the valence band offset (VBO) and electron affinity using photoemission techniques. In this study, we found that the measurements of these two values are affected by differential charging and surface contaminants, respectively. This can affect both the polarity and the strength of the derived interface dipole and therefore might have implications regarding the understanding of oxide-semiconductor band alignment. Our overall band lineup and derived interface dipole in lanthanum aluminate (LAO) heterostructures agree excellently with a popular charge-neutrality level model. This would not be possible without the accurate measurement of VBO and electron affinity in LAO heterostructures.

• 出版日期2011-5-1