Temperature‐Controlled Synthesis and Photocatalytic Performance of ZnO Nanoplatelets

Abstract

Abstract Zinc oxide nanoplatelets are successfully grown on Si(100) by CVD starting from a second‐generation Zn II precursor, Zn(hfa) 2 ·TMEDA (Hhfa = 1,1,1,5,5,5‐hexafluoro‐2,4‐pentanedione; TMEDA = N , N , N ′, N ′‐tetramethylethylenediamine). The synthesis is performed in a nitrogen + wet oxygen atmosphere under optimized conditions, at temperatures between 250 and 500 °C. Field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), and glancing incidence X‐ray diffraction (GIXRD) analyses indicate a direct correlation between morphology and microstructure. The formation of ZnO nanoplatelets, whose characteristics depend on the deposition temperature, is proposed to result from the synergistic combination of a vapor/solid (VS) mechanism and a preferential direction‐conducting growth. The chemical composition is analyzed by means of X‐ray photoelectron and energy dispersive X‐ray spectroscopies (XPS, EDXS). Finally, the photocatalytic performances of ZnO nanoplatelets in the decomposition of the azo‐dye Orange II are investigated and compared to those of uniform ZnO coatings synthesized in the absence of water vapor. The obtained results show a higher activity in the case of nanoplatelets due to their peculiar morphology.