Diffusion and incorporation of Cd in solar-grade Cu(In,Ga)Se2 layers

We examined Cd diffusion in Cu(In,Ga)Se-2 layers by means of the radiotracer technique. Depth profiles of Cd-109 were determined by ion-beam sputter-sectioning upon isothermal diffusion in the range from 197 to 425 degrees C. The Cd diffusivity can be described by the Arrhenius equation D-Cd = 4.8 x 10(-4) exp (1.04 eV/k(B)T)cm(2)s(-1). Atom-probe tomography on a sample saturated with natural Cd at 450 degrees C revealed its homogeneous incorporation over the crystal volume. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3665036]