Studying the band offset at the interface is essential to design and optimize the front and back contacts to reduce loss of photogenerated carriers in CdTe thin film solar cell. US layers were deposited at two different substrate temperatures onto ITO and ITO/SnO(2) substrates by close spaced sublimation. Photoelectron spectroscopy and sputter depth profiling was employed to determine the band offset at the TCO/CdS interface with different heat treatments. Our results show that different deposition temperatures and heat treatments including activation in CdCl(2) do not significantly alter the band alignment. (C) 2008 Elsevier B.V. All rights reserved.