PLD growth of ZnO film free from deep level emission using (La,Sr)TiO3 substrate

This paper describes the pulsed laser deposition (PLD) technology of making ZnO thin films free from deep level emission (a problem of conventionaly grown ZnO films). A visible broad peak (deep level emission) is often seen in the ZnO photoluminescence (PL) spectrum and also a sharp exciton peak. ZnO films PLD-grown on La-doped (0.5%) SrTiO3 substrates were compared with those grown on SrTiO3 substrates. When grown on La-doped SrTiO3 substrate, the deep level emission disappeared almost completely. Even when (LaSr)TiO3 film was inserted between the ZnO film and SrTiO3 substrate, deep level emission was suppressed to a large extent. Using the present result, we fabricated a NiO/ZnO/LaxSr1−xTiO3 structure and characterized it.