Epitaxial growth of large area ZrS2 2D semiconductor films on sapphire for optoelectronics

Recently, group-IVB semiconducting transition metal dichalcogenides (TMDs) of ZrS2 have attracted significant research interest due to its layered nature, moderate band gap, and extraordinary physical properties. Most device applications require a deposition of high quality large-area uniform ZrS2 single crystalline films, which has not yet been achieved. In this work, for the first time, we demonstrate the epitaxial growth of high quality large-area uniform ZrS2 films on c-plane sapphire substrates by chemical vapor deposition. An atomically sharp interface is observed due to the supercell matching between ZrS2 and sapphire, and their epitaxial relationship is found to be ZrS2 (0001)[101̄0]∥Al2O3 (0001)[112̄0]. The epitaxial ZrS2 film exhibits n-type semiconductor behavior with a room temperature mobility of 2.4 cm2·V−1·s−1, and the optical phonon is the dominant scattering mechanism at room temperature or above. Furthermore, the optoelectronic applications of ZrS2 films are demonstrated by fabricating photodetector devices. The ZrS2 photodetectors exhibit the excellent comprehensive performance, such as a light on/off ratio of 106 and a specific detectivity of 2.6 × 1012 Jones, which are the highest values compared with the photodetectors based on other group-IVB two-dimensional TMDs.