I'm interested in measuring the band alignment of colloidal grown CdSe/ZnS nanocrystals. Is there a direct or indirect method to measure that?
Band alignments are notoriously difficult to measure reliably, mostly because the position-dependent band energy is not a physical observable. Most of the techniques used for macroscopic epitaxial samples require a good ohmic contact technology, and even then are very indirect measurements, typically finding a built-in voltage from which the band alignment is inferred using oversimplified theoretical models.
The most reliable approach is to use (X-ray) photoemission spectroscopy to find the energies of well-defined core states with respect to the valence-band edge in the bulk materials, and then do measurements on samples with heterolayers that are sufficiently thin that core-level emission from both the constituents can be observed.
Of course this is a technique that works best if you have placeable and orientable samples.
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