The Applicable Guideline for the Three Criteria in Identifying p/n-Type Characteristics

In the past several decades, there has been a rapid rise in the use of transparent conducting materials (TCMs), which subsequently developed a number of criteria for identifying the p/n-type characteristics of materials. In this study, three available techniques for assessing conductive tendency were summarized and discussed, involving the branch-point energy (BPE) criterion, Mulliken electronegativity criterion, and ionization energy criterion. Combining with Density functional theory (DFT) calculations, we focus on 14 kinds of typical p-type transparent conducting materials to evaluate the applicability of the criteria. The results indicate that the BPE criterion is fitter for the material with the same valley degeneracy N_V of valence band maximum (VBM) and conduction band minimum (CBM), the Mulliken electronegativity criterion is suitable for the compound with closed-shell electronic configuration or the compounds consisting of only s and p-orbitals, and the ionization energy criterion is propitious for those materials with shallow acceptor/donor.