Influence of laser wavelength variation on the laser annealed CdTe thin films grown by thermal evaporation

Abstract

Laser annealing of CdTe thin films with two different wavelengths has been studied in this work. The CdTe thin films were grown by thermal evaporation at a deposition current of 28A and then subjected to post deposition laser annealing at two different wavelengths of 532nm (green) and 1064nm + 532nm (infrared + green). The other parameters like laser output energy, stage velocity and pulse repetition rate were kept fixed. The analyses were carried out using XRD, AFM, UV-Vis and Hall Effect Measurement system. XRD showed polycrystalline nature for all the films. AFM revealed that laser annealing didn't change the `Sq' roughness of the films significantly. The UV-Vis analysis depicted significant changes in band gap for both the laser annealed films, `T1' and `T2' on the other hand bulk concentration changed slightly upon laser annealing. FESEM images revealed the change in grain size when laser annealing was done on the CdTe thin films.