First Principle Study on Electronic Properties of Two-dimensional Atomic Crystals

First principle calculations based on density functional theory has been performed to study the work function or electron affinity and ionization potential of two-dimensional atomic crystals of carbon family, group-III-nitride family and transition-metal dichalcogenide family. Silicene is found to have the largest ionization potential and electron affinity in carbon family. The electron affinity (ionization potential) increase (decrease) with the increasing atomic number for two-dimensional group-III-nitride family, while the electron affinity and ionization potential decrease with the increasing atomic number for two-dimensional transition-metal dichalcogenide family. The results are explained with atomic configurations.