Reaction routes for the synthesis of CuInSe₂ using bilayer compound precursors

Abstract

The reaction pathways and phase evolution during synthesis of CuInSe2 (CIS) by a novel bilayer approach were investigated using in situ high‐temperature X‐ray diffraction. Two bilayer precursor structures, glass/Mo/γ‐In2Se3/β‐CuSe + β‐Cu2Se/Se and glass/Mo/γ‐In2Se3/β‐Cu2Se/Se, were examined in this study. Temperature ramp experiments revealed that the phase transformation sequence for each bilayer precursor qualitatively follows that predicted by the phase diagram and that the onset temperatures for decomposition of the sub‐binary compounds depend on the Se partial pressure. Measurement of the isothermal rate of formation of CuInSe2 at six temperatures in the range 260 to 310 °C for the γ‐In2Se3/β‐CuSe + β‐Cu2Se/Se bilayer suggests relatively slow nucleation followed by diffusion‐limited reaction with estimated activation energy of 162(±7) and 225 (±16) kJ/mol from Avrami and parabolic models, respectively. Interestingly, the measured activation energy for the same precursor in a 4 mol % H2/He ambient (108 (±8) kJ/mol) was lower than that observed in pure N2 (158 (±16) kJ/mol). The results of isothermal measurements in the temperature range 250 to 300 °C for the γ‐In2Se3/β‐Cu2Se/Se precursor film in an inert ambient are consistent with one‐dimensional diffusion‐limited growth with estimated activation energy from the Avrami and parabolic models of 194 (±10) and 203 (±12) kJ/mol, respectively. Copyright © 2012 John Wiley & Sons, Ltd.

CuInSe2 Formation from CuSe/In2Se3 and Cu2Se/In2Se3 Powders: Reaction Kinetics and Mechanisms

“…Diffusion of Cu + into the γ‐In 2 Se 3 agglomerates and the CIS formation is facilitated by the liquid phase covering the γ‐In 2 Se 3 and CIS crystallites, enhancing Cu + diffusion . Therefore, it seems reasonable that the CIS formation kinetics were dominated by the diffusion of Cu + ions in the samples calcined under a Se atmosphere …”

“…This indicated the reaction kinetics may be dominated by In 3+ diffusion . The reaction path and phase evolution during CIS synthesis strongly depends on the kinds of binary selenides used and the annealing atmosphere . Chen and Wang investigated CIS formation from Cu 2 Se and In 2 Se 3 compounds in Se and the non‐Se atmospheres.…”

“…23 The reaction path and phase evolution during CIS synthesis strongly depends on the kinds of binary selenides used and the annealing atmosphere. 24,25 Chen and Wang 24 investigated CIS formation from Cu 2 Se and In 2 Se 3 compounds in Se and the non-Se atmospheres. They found that reactions occurred through solid-solid reaction in the non-Se environment, but reactions occurred by a liquid-solid reaction due to the formation of low-melting Se-rich Cu-Se compounds during reaction in the Se environment.…”

Insight into the mechanism of Sb promoted Cu(In,Ga)Se2 formation

“…For most of the well-developed fabrication processes of CIGS thin films, two common steps are often involved: (1) reactions of binary selenides of Cu, In, and Ga to form CIGS compound [6], usually in the selenization of deposited metals [7], or preparation of CIGS nanoparticles [8]; and (2) crystalline growth of CIGS compound to form columnar grains, usually in annealing processes [9]. Based on the mechanism understanding of these two steps, state-of-the-art strategies have been developed to improve properties of CIGS materials and corresponding CIGS thin films.…”

Adventures in Cu‐chalcogenide solar cells. A special issue for the occasion of the 65th birthday of Prof. Dr.‐Ing. Hans‐Werner Schock

“…The reaction paths by which the absorber layers with optimal PV characteristics can be obtained from thermal reaction of stacked precursor layers are studied and described by Krishnan et al . in their contribution.…”