The order-disorder transition in Cu2ZnSnS4 – A neutron scattering investigation

•The order-disorder transformation of Cu2ZnSnS4 follows a Landau‐type behavior for a second order transition.•The critical exponent β is 0.57±0.06.•The critical temperature was determined as 552±2 K.•A fully ordered (within the standard deviation) Cu2ZnSnS4 sample was synthesized.

In this work a series of stoichiometric Cu2ZnSnS4 (CZTS) samples annealed at different temperatures in the range of 473–623 K were investigated. The temperature dependence of the Cu/Zn-order-disorder behavior was analyzed by neutron powder diffraction measurements. Cu fully occupies the 2a and Sn the 2b position within the whole temperature range. For Zn and the remaining Cu on sites 2d and 2c, a clear change from ordered to disordered kesterite structure is found. The critical temperature Tc for this Landau-type second order transition was determined as 552±2 K. It was found that in Cu2ZnSnS4 very long annealing times are necessary to reach equilibrium at low temperatures.

Graphical abstractThe order-disorder transition in Cu2ZnSnS4 was investigated using neutron diffraction techniques on samples annealed in the temperature range of 473–623 K. The critical temperature Tc for this Landau-type second order transition was determined as 552±2 K.Figure optionsDownload full-size imageDownload as PowerPoint slide