Stable pH sensitivity of LaAlO3/SrTiO3 interfacial electronic gas

Probing pH value is essential for many applications. The request of developing stable and highly sensitive pH sensor with small size are increased recently, this is a challenge to the traditional glass pH sensors. This work investigated the pH sensing performance of the novel two-dimensional electronic gas (2DEG) at the LaAlO3/SrTiO3 heterostructure interface discovered recently. The experimental results demonstrated that the devices host excellent sensing ability to the pH value of aqueous solutions. Quite stable output current is realized for a given pH value, and the output current is linearly dependent on pH value as required by sensor applications. This work would prompt the application research of LaAlO3/SrTiO3 heterostructure and design of new generation of advanced pH sensors. [Display omitted] •A stable pH sensor was designed and fabricated at the LaAlO3/SrTiO3 heterostructure.•The sensor demonstrated good performances with prospection of improvement in future.•The sensor is easy to be fabricated which would reduce the cost of potential products much.