The operation of thin-film electronic devices is dictated by the band alignment at the interfaces of the various layers. While a number of methods for measuring the depth profile of the electrical potential at interfaces have emerged, these are typically arduous to perform and involve the use of ultrahigh vacuum, complicated sample preparation, and/or suffer from poor resolution. Here a method to directly map the depth profile of the electrical potential is presented at an interface in air by growing a sample with an intentional thickness gradient and correlating the surface potential, measured using (macroscale) scanning Kelvin probe, to the thickness at each point. The approach is nondestructive and rapid, is ideal for large substrates and films grown with an inherent thickness gradient. It enjoys very high depth (2 nm) and energy resolution (5 meV), comparable to other methods. In this work, the method is developed and demonstrated on a TiO2|Co3O4 all-oxide junction and a depletion width of only 8.6 ± 3.8 nm in the Co3O4 layer is shown.
|Journal||Advanced Materials Interfaces|
|State||Published - 21 Aug 2017|
Bibliographical noteFunding Information:
K.J.R. received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement no. 659774. This research was supported Israel Science Foundation (grant no. 1729/15) and the Israeli National Nanotechnology Initiative (INNI, FTA project).
© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
- Kelvin probe
- band alignment
- electrical characterization
- solar cells