Effect of substrate temperature on the optical constants of zincphthalocyanine thin films

The influence of the film thickness and substrate temperature on optical constants of the vacuum evaporated ZincPhthalocyanine (ZnPc) thin films have been reported in this paper. The direct and allowed optical band gap energy has been evaluated from the (αhυ)2 vs. (hυ) plots. The optical constants such as extinction coefficient (kf) and refractive index (n) have been evaluated from the transmittance values and the observed results strongly dependent on substrate temperature and film thickness. The low values of the refractive index have been observed for the films prepared at Ts=200°C. The change in crystallanity and phase transformation affect the optical constants and the lower values of the optical constants will leads to the good quality of the ZnPc thin films.