Cu2ZnSnS4 (CZTS) thin films were successfully prepared by sulfurization of ion bean sputtered precursors on soda-lime glass substrate. The single phase of stannite-type structure CZTS films were obtained as revealed in EDS and XRD analysis when the ratios of the constituents of CZTS thin films are close to stoichiometric by optimizing the conditions of precursor preparation and sulfurization. A low sheet resistivity as about 0.156 Ω·cm and a high absorption coefficient as 1×104 cm-1 were achieved in this method by Hall effect measurements and UV-VIS spectrophotometer. The optical band-gap energy of the CZTS sample is about 1.51 eV, which is very close to the optimum value for a solar-cell absorber.
Cu2ZnSnS4 (CZTS) thin films were successfully fabricated on glass substrates by sulfurizing Cu-Sn-Zn multilayer precursors, which were deposited by ion beam sputtering and RF magnetron sputtering, respectively. The structural, electrical and optical properties of the prepared films under various processing conditions were investigated in detail. Results showed that the as-deposited CZTS thin films with the precursors by both ion beam sputtering and RF magnetron sputtering have a composition near stoichiometric. The crystallization of the samples, however, has a strong dependence on the atomic percent of constituents of the prepared CZTS films. A single phase stannite-type structure CZTS with a large absorption coefficient of 104/cm in the visible range could be obtained after sulfurization at 520℃ for 2 h. The samples relative to the RF magnetron sputtering showed a low resistivity of 0.073 ?cm and band gap energy of about 1.53 eV. The samples relative to the ion beam sputtering exhibited a resistivity of 0.36 Ωcm and the band gap energy is about 1.51 eV.
ZHANG Jun & SHAO LeXi School of Physical Science and Technology, Zhanjiang Normal University, Zhanjiang 524048, China
The feasibility of a new fabrication route for N and Ga codoped p-type ZnO thin films on glass substrates, consisting of DC sputtering deposition of Zn3N2 ：Ga precursors followed by in situ oxidation in high purity oxygen, has been studied. The effects of oxidation temperature on the structural, optical and electrical properties of the samples were investigated by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, optical transmittance and Hall effect measurements. The results were compared to a control film without Ga. XRD analyses revealed that the Zn3N2 films entirely transformed into ZnO films after annealing Zn3N2 films in oxygen over 500 ℃ for 2 h. Hall effect measurements confirmed p-type conduction in N and Ga codoped ZnO films with a low resistivity of 19.8 Ω·cm, a high hole concentration of 4.6× 10^18 cm^-3 and a Hall mobility of 0.7 cm^2/（V·s）. These results demonstrate a promising approach to fabricate low resistivity p-type ZnO with high hole concentration.
