First-principles calculations of electronic structure and optical properties of Boron-doped ZnO with intrinsic defects

摘要

This study adopted first-principles calculations to evaluate the effects of intrinsic defects on the electronic structure and optical properties of Boron-doped ZnO (BZO). Four types of defect were considered: non-defective (B_(Zn)), Zn vacancies (V_(Zn)), O vacancies (V_O), and interstitial Zn (Zn_i). Calculations of formation energy illustrate that O-rich conditions tend to induce V_(Zn), while O-poor conditions tend to induce V_O and Zn_i. With respect to electric properties, V_(Zn) defects in BZO decrease carrier concentration as well as mobility, which consequently decreases the conductivity of BZO. The existence of V_O or Zn_i defects in BZO leads to n-type conductive characteristics and increases the optical band gap. The existence of Zn_i defects in BZO also increases the effective mass, which decreases the mobility and conductivity of BZO. As for the optical properties, the introduction of V_(Zn) to BZO leads to an increase in transmittance in the visible light region, but a decrease in the UV region. The introduction of intrinsic V_O and Zn_i defects to BZO leads to a significant decrease in transmittance in the visible as well as UV regions. The calculated results were also compared with experimental data from the literature.