High conductivity of Ga-doped rock-salt ZnO under pressure:Hint on deep-ultraviolet-transparent conducting oxides

• Published in: Applied physics letters 2006-01, Vol.88 (1), p.011910-011910-3
• Main Authors: Segura, A., Sans, J. A., Errandonea, D., Martinez-García, D., Fages, V.
• Format: Article
• Language: English
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/1.2161392

This letter reports on transport and optical experiments under pressure in thin films of Ga-doped ZnO in both the wurtzite and rock-salt phases. The conductivity of heavily Ga-doped ZnO thin films is shown to decrease by only a factor of 2 in the wurtzite-to-rock-salt phase transition, occurring at about 11.5 GPa, while the optical gap increases from 4 to more than 5 eV. Ga-doped rock-salt ZnO is shown to behave as a deep-ultraviolet-transparent conducting oxide, with resistivity values as low as 10 − 3 Ω cm . The analysis of Burstein-Moss shift and free carrier absorption in rock-salt ZnO yield an estimation of the electron-hole reduced effective mass and electronic dielectric constant. Given the similarity between the electronic structures of rock-salt ZnO under pressure and rock-salt Mg x Zn 1 − x O at ambient pressure, this alloy could be a good deep-ultraviolet-transparent conducting oxide.