Positron annihilation study of defects in electron-irradiated single crystal zinc oxide

Role of Alkali Metal in BiVO4 Crystal Structure for Enhancing Charge Separation and Diffusion Length for Photoelectrochemical Water Splitting

“…The diffusion length of the implanted positrons is given in Figure c (inset). For pristine BiVO 4 , the diffusion length of the positron was 9.65 ± 0.92 nm, which was shorter compared to the bulk diffusion length in crystalline oxides . The shorter diffusion length in BiVO 4 films confirmed the presence of negatively charged (cation vacancy) or neutral vacancy defects or vacancy clusters (Bi or V vacancy defects), which act as a potential trap for positrons.…”

“…For pristine BiVO 4 , the diffusion length of the positron was 9.65 ± 0.92 nm, which was shorter compared to the bulk diffusion length in crystalline oxides. 46 The shorter diffusion length in BiVO 4 films confirmed the presence of negatively charged (cation vacancy) or neutral vacancy defects or vacancy clusters (Bi or V vacancy defects), which act as a potential trap for positrons. On the other hand, K doping demonstrated a decrease in the characteristic S-parameter and a slight increase in the diffusion length (13.49 ± 1.78 nm), indicating a small reduction in the defect density compared to pristine BiVO 4 films.…”

Band gap and defect engineering of bismuth vanadate using La, Ce, Zr dopants to obtain a photoelectrochemical system for ultra-sensitive detection of glucose in blood serum

“…The positron diffusion length determined for un-doped BiVO 4 films (∼13.49 nm) is much shorter compared to the bulk diffusion length in crystalline oxides. 36 It confirmed that the open-volume defects, which are efficient traps of the positrons like the negatively charged (cation vacancy) or neutral vacancy defects or vacancy clusters (Bi or V vacancy defects), are present in the un-doped BiVO 4 film. On doping of Ce, insignificant changes are observed in the characteristic S -parameter and diffusion length compared to un-doped BiVO 4 .…”