Secondary-Phase-Assisted Grain Boundary Migration in CuInSe_{2}.

Significant structural evolution occurs during the deposition of CuInSe_{2} solar materials when the Cu content increases. We use in situ heating in a scanning transmission electron microscope to directly observe how grain boundaries migrate during heating, causing nondefected grains to consume highly defected grains. Cu substitutes for In in the near grain boundary regions, turning them into a Cu-Se phase topotactic with the CuInSe_{2} grain interiors.

Formation of GaP/Si(100) Heterointerfaces in the Presence of Inherent Reactor Residuals.

Adequate silicon preparation is a prerequisite for defect-free III-V growth on Si. We transfer the silicon processing from clean to GaP containing metalorganic vapor phase epitaxy reactors, where we monitor the entire process in situ with reflection anisotropy spectroscopy and analyze the chemical composition of the surface with X-ray photoelectron spectroscopy. Beyond a certain submonolayer threshold value of (Ga,P) residuals found on the Si(100) surface, GaP grows with an inverted majority sublattice.