ZnO:Al Thin Films with Buffer Layers Fabricated via Nitrogen Mediated Crystallization: Effects of N₂/Ar Gas Flow Rate Ratio

Abstract

Effects of N 2 /Ar gas flow rate ratio on the crystallinity of sputtered ZnO films fabricated via nitrogen mediated crystallization (NMC) have been clarified. Introduction of small amount of N 2 (N 2 /Ar = 4/20.5 sccm) drastically improves the crystal orientation and enlarges grain size of the NMC-ZnO films, where FWHM of XRD patterns for 2θ-ω and ω scan of (002) plane are 0.17° and 2.6°, respectively. A further increase in N 2 /Ar flow rate ratio deteriorates the crystallinity, since excess N atoms in the films disarrange the crystal structure of ZnO. Furthermore, ZnO:Al (AZO) films with high crystallinity have been successfully fabricated by utilizing the NMC-ZnO films deposited at N 2 /Ar = 4/20.5 sccm as buffer layers. 100-nmthick AZO films with a resistivity of 6.8×10 -4 Ωcm and an optical transmittance higher than 80% in a wide wavelength range of 500 nm to 1500 nm has been obtained.

Fabrication of ZnInON/ZnO multi-quantum well solar cells

“…Seven or 15 periods of ZnInON(6 nm)/ZnO(10 nm) MQWs were deposited on two types of templates: one is single-crystalline ZnO films prepared on c-plane sapphire substrates, and another is poly-crystalline ZnO films deposited on quartz glass substrates. Here, single-crystalline ZnO templates were prepared by using the nitrogen-mediated crystallization (NMC) method [23][24][25][26][27][28][29][30][31], which is a method for fabrication of highquality epitaxial films on large lattice-mismatched substrates. Despite the large lattice mismatch (18%) between ZnO and c-plane sapphire, single-crystalline ZnO films that have atomically flat surface were fabricated by the NMC method.…”