Enhancement in optical characteristics of c-axis-oriented radio frequency–sputtered ZnO thin films through growth ambient and annealing temperature optimization. (1st August 2017)

• Record Type: Journal Article
• Authors: Murkute, Punam; Ghadi, Hemant; Saha, Shantanu; Pandey, Sushil Kumar; Chakrabarti, Subhananda
• Is Part Of: Materials science in semiconductor processing. Volume 66(2017)
• Page Start: 1
• Page End: 8
• Publication Date: 2017-08-01
• Subjects: RF sputtering -- Photoluminescence -- HRXRD -- AFM; Semiconductors -- Periodicals; Integrated circuits -- Materials -- Periodicals; Semiconducteurs -- Périodiques; Circuits intégrés -- Matériaux -- Périodiques; Electronic journals; 621.38152
• DOI: 10.1016/j.mssp.2017.03.026
• Languages: English
• ISSNs: 1369-8001

Abstract

Abstract: High-quality radio frequency–sputtered ZnO were grown on Si substrates at 400 °C at various partial gas pressures (Ar/Ar+O2). Subsequently, to remove as-grown defects, high temperature annealing from 700 to 900 °C on as-grown samples in constant oxygen flow for 10 s was performed. X-ray diffraction study confirmed the formation of highly crystalline films with a dominant peak at (002). The sample grown in 50% Ar and 50% O2 ambient exhibited the lowest linewidth (2θ=~0.2728°) and highest stoichiometry. Grain size of the as grown samples decreased with increase in the partial pressure of oxygen till a certain ratio (1:1), and photoluminescence (PL) improved with increase in annealing temperature. Low-temperature (18 K) PL measurements showed a near-band-edge emission peak at 3.37 eV, and the highest peak intensity (more than six orders compared to others with narrow linewidth of ~0.01272 eV) was exhibited by the sample annealed at 900 °C and was six orders higher than that of the as-grown sample. All as-grown samples exhibited dominant visible-range peaks due to emission from defect states.