Preparation And Characteristic Of Ti Or Cr Doped CuGaS₂ Intermediate Band Thin Film Materials

Intermediate band solar cells can reach as high as 63.1%in theoretical limit efficiency.It is much higher than that of conventional solar cells and multi-junction solar cells.Therefore,it has become a hot topic in the field of solar cells research.According to the theory of the intermediate band,the optimal band gap value for the base material is about 2.4 eV.The optical band gap of chalcopyrite semiconductors CuGaS₂ is just 2.4 eV,which is one of the best base materials in theory.The intermediate band can be formed Ti or Cr doped CuGaS₂.It shows that the preparation and photoelectric characteristics of Ti or Cr doped CuGaS₂ intermediate band thin films in this paper.Ti or Cr doped CuGaS₂ intermediate band thin films were prepared by magnetron sputtering-annealing two-step method in the paper.The CuGaS₂ and TiS₂/Cr₂S₃ target were sputtered onto the glass substrate to prepare the prefabricated film at the same time.The microstructure and photoelectric characteristics of the intermediate band thin films were studied by means of the X-ray diffraction?XRD?,the UV-vis-NIR light absorption spectra?UV?,the scanning electron microscopy?SEM?and EDAX.Results show that at 834 nm?1062 nm and 1542 nm,three additional subband edge responses were observed to show the formation of a half-filled intermediate band.And Ti doped CuGaS₂ is 550?among the best annealing temperature.It shows that Ti doping introduces the intermediate band in CuGaS₂.With the changing of Ti doping amount,the position of subband gap is without apparent movement.There are also three subband gap absorption edges in the optical absorption spectrum of Cr-CuGaS₂ thin film.With the increasing of Cr doping amount,the absorption band edge is gradually redshifted and the optical band gap is gradually narrowed.