Investigation of Induced Recrystallization and Stress in Close-Spaced Sublimated and Radio-Frequency Magnetron Sputtered CdTe Thin Films

We have induced recrystallization of small grain CdTe thin films deposited at low temperatures by close-spaced sublimation (CSS), using a standard CdCl₂ annealing treatment. We also studied the changes in the physical properties of CdTe films deposited by radio-frequency magnetron sputtering after the same post-deposition processing. We demonstrated that the effects of CdCl₂ on the physical properties of CdTe films are similar, and independent of the deposition method. The recrystallization process is linked directly to the grain size and stress in the films. These studies indicated the feasibility of using lower-temperature processes in fabricating efficient CSS CdTe solar cells. We believe that, after the optimization of the parameters of the chemical treatment, these films can attain a quality similar to CSS films grown using current standard conditions.