Heterotwin Zn3P2 superlattice nanowires: the role of indium insertion in the superlattice formation mechanism and their optical properties

Zinc phosphide (Zn3P2) nanowires constitute prospective building blocks for next generation solar cellsdue to the combination of suitable optoelectronic properties and an abundance of the constitutingelements in the Earth’s crust. The generation of periodic superstructures along the nanowire axis couldprovide an additional mechanism to tune their functional properties. Here we present the vapour–liquid–solid growth of zinc phosphide superlattices driven by periodic heterotwins. This uncommon planardefect involves the exchange of Zn by In at the twinning boundary. Wefind that the zigzag superlatticeformation is driven by reduction of the total surface energy of the liquid droplet. The chemical variationacross the heterotwin does not affect the homogeneity of the optical properties, as measured by catho-doluminescence. The basic understanding provided here brings new propsects on the use of II–V semi-conductors in nanowire technology