Modeling hydrogen in CuInSe2 and CuInS2 solar cell materials using implanted muons

Muon spin rotation experiments on CuInSe2 and CuInS2 were performed in the context of a study on the effect and behavior of hydrogen on chalcopyrite s olar cell materials. The microscopic information delivered by implanted pos itive muons can be applied to the hydrogen case by analogy. It was found th at the major fraction of the muons is in a diamagnetic environment but, at low temperatures, a fraction of 5-10 % has a paramagnetic surrounding. In C uInSe2 the site of the diamagnetic muon is tentatively assigned to the anti bonding site close to Se and the onset of muon diffusion on a microsecond t ime scale is observed between 200 and 250 K. The pre-exponential factor for the hop rate and the activation energy are v(0)=3.4 x 10(10) s(-1) and E-a =220 meV. Above 250 K trapping occurs. The diffusion behavior in CuInS2 is similar, but the onset is shifted by 50 K to higher temperatures. [S0163-18 29(99)00704-3].