Co-axial core–shell ZnMgO/ZnO NWs

• Published in: Solid-state electronics 2015-02, Vol.104, p.126-130
• Main Authors: Rivera, Abdiel, Mazady, Anas, Anwar, Mehdi
• Format: Article
• Language: English
• Subjects: Activation energy; Buffers; Co-axial ZnMgO/ZnO core–shell; Constants; Core-shell structure; Crystal structure; Gas sensor; Gas sensors; Methyl alcohol; Nanorods; Shells; Traps; Zinc oxide
• ISSN: 0038-1101; 1879-2405
• DOI: 10.1016/j.sse.2014.08.010

•First co-axial Zn0.9Mg0.1O core–shell structure grown on p-Si via MOCVD.•Adsorption and desorption of CH3OH on core–shell and nanorod surfaces was compared.•Core–shell exhibited 3 times faster response than nanorods.•High reported sensitivity of 37% at temperature not exceeding 75°C. We report the first co-axial Zn0.9Mg0.1O/ZnO core–shell structures, on p-Si substrates, grown using metal–organic chemical vapor deposition (MOCVD). With ZnO buffer serving as a seed layer, vertically aligned ZnMgO NWs with a Mg mole fraction of 10% were grown, serving as the template for the growth of ZnO shell. The core and the shell have c-lattice constants of 5.1868Å and 5.1996Å, respectively, with no measurable strain at the core. The core–shell structure is single crystalline with an abrupt ZnMgO–ZnO interface. Performance of ZnMgO/ZnO core–shell structure as a gas sensor is reported. The room temperature response magnitude (RM) was found to be between 2% and 7% for a methanol concentration in the range of 1–15ppm. RM as high as 37% is measured at 75°C for higher methanol concentration. Co-axial ZnMgO/ZnO core–shell structures are demonstrated to be a better alternative than ZnO nanorods as gas sensors.