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

Abstract

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 (BZn), Zn vacancies (VZn), O vacancies (VO), and interstitial Zn (Zni). Calculations of formation energy illustrate that O-rich conditions tend to induce VZn, while O-poor conditions tend to induce VO and Zni. With respect to electric properties, VZn defects in BZO decrease carrier concentration as well as mobility, which consequently decreases the conductivity of BZO. The existence of VO or Zni defects in BZO leads to n-type conductive characteristics and increases the optical band gap. The existence of Zni defects in BZO also increases the effective mass, which decreases the mobility and conductivity of BZO. As for the optical properties, the introduction of VZn to BZO leads to an increase in transmittance in the visible light region, but a decrease in the UV region. The introduction of intrinsic VO and Zni 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.