Single crystal growth and phase stability of photovoltaic grade ZnSiP2 by flux technique
ZnSiP2 is a potential optoelectronic material with possible application in lasers, LED's, photonic integrated circuits, and photovoltaics. The development of ZnSiP2 as a photovoltaic material could address the current technological challenge of implementing a monolithic top cell on silicon for tandem photovoltaics. In this work we present a detailed description of the growth of ZnSiP2 single crystals, which has enabled thorough optoelectronic characterization. A flux growth technique was used, under various conditions, to grow ZnSiP2 single crystals in Zn solution. The results of these growth experiments, along with analysis of previously determined phase diagrams, show that three secondary phases form as a result of the Zn flux growth technique: Zn3P2, Si, and the remaining Zn flux. Potential reasons for the formation of these particular phases are discussed, but their presence is found to be non-detrimental, and they can easily be removed. The resulting single crystals are high purity and enable the characterization of the fundamental optoelectronic properties of ZnSiP2.
Critical review of the growth of II–IV–V2 compounds
Abstract Various II-IV-V 2 compounds have been grown in single crystal form by melt, vapour and metal solution growth techniques. The literature on this is summarised in a table for the 24 known compounds. The application of accelerated crucible rotation techniques and careful temperature programming to metal solution growth has produced a tenfold increase in crystal size.
Dielectric definition of ionicity
Abstract A precise criterion is proposed for testing definitions of ionicity. The dielectric definition is ten times more accurate than Pauling's definition, which in turn is comparable to results obtained using the Coulson valence bond method.