Sub-100 nm resolution 3-D tomography of CZTSe using transmission X-ray Microscopy

Transmission X-ray Microscopy (TXM) is a powerful technique with a theoretical resolution down to 30 nm that can be used to fill the mesoscale gap between the atomic scale resolution of atom probe tomography (APT) and macroscale resolution of energy dispersive spectroscopy (EDS). For this study, thin film solar cells based on Cu2ZnSnSe4 (CZTSe) absorber layers with Zn/Sn ratios of 1.0 and 1.4 were characterized using element-specific TXM and 3-D tomographic reconstruction. The resulting data are 3-D concentration fields for Cu, Zn, Sn, and Se. From these data we analyze compositional fluctuations at a previously inaccessible combination of sampling volume and resolution.