The influence of Ca doping in Bi₂O₂Se: A first-principles investigation

Bi₂O₂Se, as a member of bismuth oxychalcogenides, is regarded as a promising candidate for optoelectronic applications, such as phototransistors, photodetectors, pulsed lasers and photodiodes. Throughout the research progress of Bi₂O₂Se, the crystal quality of Bi₂O₂Se plays an important role. Using the first-principles calculations, we study the influence of Ca, one of the most abundant elements on the earth, doping in Bi₂O₂Se. We find that Ca doping is easy in Bi₂O₂Se which further induces substitution point defect Ca_Bi. The presence of Ca_Bi introduces a deep donor level which is favorable for a short carrier lifetime. Thus, Ca doping may be used to improve switching characteristics of Bi₂O₂Se-based diodes and transistors.