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

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 T-c 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. (C) 2016 Elsevier Inc. All rights reserved.