| Materials with a direct tunable bandgap in the range of 1.0 to 2.0 eV offer potential as next generation materials for energy generation application. Many of these materials, however, contain expensive and rare elements, such as indium and gallium, motivating efforts to identify alternative materials composed of earth abundant elements. ZnSnN2, a relatively unexplored member of the family of ZnIVN2 semiconductors is one such compound.;In this work, samples of ZnSnN2 were prepared epitaxially by the plasma-assisted molecular beam epitaxy (MBE) technique, which is capable of producing high quality crystalline thin films with device quality electronic properties. Films were characterized using electron microscopy, x-ray and electron diffraction, x-ray photoelectron techniques and optical absorption. While predicted to have an orthorhombic structure with a bandgap of 2.0 eV, our results indicate that a wurtzite structure with narrow bandgap energy is also possible. This is due to the effects of disorder in the Zn and Sn cation sublattice, a conclusion supported by detailed comparison to density functional theory prediction. Consequently this behavior may offer a valuable material property tuning parameter that can be adjusted through sample growth, obviating the need for traditional alloying approaches. |
