Band gap modification of spray pyrolysed ZnS films by doping and thermal annealing

Özet

ZnS thin films are widely used in solar cells as window material.Optical and electrical properties of the films such as band gapenergy and resistivity directly affect device performance. In thiswork it was shown that properties of ZnS films can be changed bydoping and thermal annealing. Therefore, films with convenientparameters can be chosen for the fabrication of any device. ZnS filmswere fabricated by spray pyrolysis technique. Zinc chloride andthiourea used as sources of Zn and S respectively. Films were grownon 350oC hot substrates. Furthermore 1, 5, 10, 15 % doped filmsprepared by addition of boric acid into the solution. Structural,optical and electrical properties of the films were examined by SEM,XRD, optical transmission and resistivity measurements. Later onall films annealed in air at 350oC for 30 min. All measurements weredone also for annealed films. Effects of doping and thermalannealing on the band gap energy and resistivity of the films wereshown. Band gap energies of the films were between 3.37-3.82 eVand surface resistivities were between 257.2-12.5 M𝛺.