Existence of off-stoichiometric single phase kesterite

• Cu2ZnSnS/Se4 samples synthesized by solid state reaction.
• WDX spectroscopy and the structural characterization by X-ray diffraction.
• Proved of existence off single phase off-stoichiometric Cu2ZnSnS/Se4.

In this work the flexibility of the kesterite structure is discussed. It is shown that kesterite type CZTS and CZTSe can deviate from stoichiometric composition by the formation of intrinsic point defects leading to different off-stoichiometric kesterite types. For this study off-stoichiometric CZTS and CZTSe powder samples have been synthesized by solid state reaction from pure elements. Their chemical composition was determined by WDX spectroscopy and the structural characterization was conducted by X-ray diffraction. Amongst the studied 49 samples, a number of them have been identified to contain only an off-stoichiometric kesterite type phase which exhibit Cu-poor/Zn-rich composition. On the other hand, Cu-rich/Zn-poor kesterite type CZTS and CZTSe always coexists with secondary phases. Thus it has been demonstrated, that the kesterite type structure can self-adapt to Cu-poor and Cu-rich compositions in CZTS and CZTSe without any structural change except the cation distribution.

In this work the flexibility of the kesterite structure is discussed. It is shown that kesterite type CZTS/Se can deviate from stoichiometric composition by the formation of intrinsic point defects leading to different off-stoichiometric kesterite types. For this study 49 off-stoichiometric CZTS/Se powder samples have been synthetized by solid state reaction from pure elements. Their chemical composition was determined by WDX spectroscopy and the lattice parameters were obtained by X-ray diffraction. Amongst the studied samples, a number of them have been identified to contain only an off-stoichiometric kesterite type phase which exhibit Cu-poor/Zn-rich composition. On the other hand, Cu-rich/Zn-poor kesterite type CZTS/Se always coexists with secondary phases. It has been demonstrated, that the kesterite type structure can self-adapt to copper-poor and copper-rich compositions in CZTS/Se without any structural change except the cation distribution.Figure optionsDownload as PowerPoint slide