Electrical conductivity of p-type BiOCl nanosheets

Abstract

High quality BiOCl nanosheets were fabricated using facile, room temperature hydrolysis of Bi(NO₃)₃ and HCl. The resulting nanosheets had dimensions of 500 nm with the exposed {001} facet. The band gap of the nanosheets was found to be 3.34 eV with conduction and valence band edges at −3.63 eV and −6.97 eV with respect to vacuum, respectively. The electrical conductivity of drop-cast BiOCl nanosheets was measured between aluminum patterned electrodes as a function of temperature and oxygen partial pressure (pO₂). The activation energy for conduction in BiOCl was found to be 862 meV in the temperature range of 300–425 K and below 1000 mbar. The electrical conductivity varied with pO₂, indicating σ ∝ pO₂^1/4.05 and σ ∝ pO₂^1/32 for low and sub atmospheric pressures, respectively. A prototypical device for low temperature (425 K) O₂ sensing was demonstrated.