Thermal diffusion of indium in single crystals of the layered compounds 2H-TaSe2, and TaS2, parallel to the layers, was studied. Measurements were performed in situ in a scanning electron microscope equipped with an X-ray energy dispersive system. The distance of the diffusing indium front into the crystal was determined as a function of time from secondary electron image as well as from X-ray line scans for indium taken at different time intervals. The diffusion coefficients D were found by fitting the data to <r2> = 2Dt, where <r2> was the mean square displacement in time, t. The diffusion coefficients thus obtained were 1.5 x 10-12, 3.8 x 10-12, 7.7 x 10-12 and 17.5 x 10-12m2/s with an uncertainty of about 10% at 351, 375, 411 and 458K respectively for TaSe2. The values for TaS2 were 5.3 x 10-11, 9.5 x 10-11, 1.7 x 10-10 and 3.6 x 10-10m2/s at 345, 369, 388 and 437K, respectively. The activation energy E0 of indium diffusion, using D = D0 e-E0/kT, were determined to be 0.32 and 0.27eV for TaSe2 and TaS2, respectively. The results showed that diffusing indium atoms put severe stress on the layers as they intercalated between them. This stress was relieved by buckling of the layers and these buckling features were clearly visible in secondary electron images.

Thermally Activated Diffusion of Indium into Layered Materials 2H-TaSe2 and TaS2. O.Rajora: Physica Status Solidi A, 2006, 203[3], 493-6