Insight into the interatomic competitive mechanism for interfacial stability of room temperature liquid GaInSn/Cu electrode

Room temperature Ga-based alloys have received more and more attentions due to their unique advantages in these applications of stretchable and wearable electronics. In this paper, the interfacial stability of liquid GaInSn/ Cu interface was systematically investigated. From the perspective of crystallography, the orientation relationship between the nucleation and growth of intermetallic compounds and Cu substrate are discussed according to plane-on-plane matching model and edge-to-edge matching model. The required standard formation enthalpy and bond enthalpy of as-formed intermetallic compounds are estimated based on the elemental condensed bond enthalpy and crystal cluster theory. For the ternary GaInSn system, the competitive reactive mechanism between different reactive atomic pairs was revealed and discussed from the thermodynamic view, which verified that the rationality of the formed intermetallic compounds only consisting of Cu and Ga. Besides, we confirmed that the wetting behavior of GaInSn on Cu substrate was determined by the affinity and close contact probability of different atomic pairs.