Fabrication and properties of p-type K doped Zn1−xMgxO thin film

A series of K doped Zn1−xMgxO thin films have been prepared by pulsed laser deposition (PLD). Hall-effect measurements indicate that the films exhibit stable p-type behavior with duration of at least six months. The band gap of the K doped Zn1−xMgxO films undergoes a blueshift due to the Mg incorporation. However, photoluminescence (PL) results reveal that the crystallinity decreased with the increasing of Mg content. The fabricated K doped p-type Zn0.95Mg0.05O thin film exhibits good electrical properties, with resistivity of 15.21 Ω cm and hole concentration of 5.54 × 1018 cm−3. Furthermore, a simple ZnO-based p–n heterojunction was prepared by deposition of a K-doped p-type Zn0.95Mg0.05O layer on Ga-doped n-type ZnO thin film with low resistivity. The p–n diode heterostructure exhibits typical rectification behavior of p–n junctions.

► This work discussed the effect of Mg and K codoped into ZnO. The Zn0.95Mg0.05O:K film obtained at 500 °C with 40 Pa O2 exhibits a better p-type property, which has an electrical resistivity of 15.21 Ω cm, and a carrier concentration of 5.54 × 1018 cm−3. ► The rectification of the p-Zn0.95Mg0.05O:K/n-ZnO:Ga heterojunction device also confirms the p-type property of the Zn0.95Mg0.05O:K film. ► Our results indicate that p-type Zn1−xMgxO:K films may show a promising future in the fabricating of p-type ZnO film.