Influence of the thickness on the morphology and sensing ability of thermally-deposited tellurium films

19th International Summer School on Vacuum, Electron and Ion Technologies

Hristova-Vasileva, T.^1 ; Bineva, I.^1 ; Dinescu, A.^2 ; Nesheva, D.^1 ; Arsova, D.^1 ; Pejova, B.^3

Georgi Nadjakov Institute of Solid State Physics, Bulgarian Academy of Sciences, 72 Tsarigradsko Chaussee, Sofia

1784, Bulgaria^1

National Institute for RandD in Microtechnologies, IMT Bucharest, 126 Erou Iancu Nicolae Str., Bucharest

077190, Romania^2

Faculty of Natural Sciences and Mathematics, Sts. Cyril and Methodius University, P.O. Box 162, Skopje

1001, Macedonia^3

关键词: Ammonia vapors;    Morphology evolution;    Nano-objects;    Nanosheet structure;    Root mean square roughness;    Sensing abilities;    Thickness of the film;    Z-directions;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/700/1/012037/pdf
DOI  :  10.1088/1742-6596/700/1/012037

来源: IOP

【 摘 要 】

Tellurium films with nominal thicknesses of 30, 90 and 300 nm were prepared by thermal evaporation in vacuum at a low deposition rate of 0.3 nm/s. The morphology evolution with the increase of the film thickness was observed by scanning electron microscopy and atomic force microscopy. Nanorods with a width of about 40 nm were observed on the thinnest films surface. On the 90 nm thick films, the formations grew in priority in the z-direction to nanoblades with the same width, but a length of about 100 nm. The further increase of the thickness led to an increase of the 2D nanoobjects' width and length and formation of a stacked nanosheet structure. The surface root-mean-square roughness (Sq) increased with the thickness of the films. Preliminary investigations of the sensing ability of the as-deposited tellurium films with different thicknesses towards water (H2O), ethanol (C2H5OH), acetone (C3H5OH), and ammonia (NH3) vapors were performed by measuring the vapor-induced changes in the film dark current. The films showed appreciable response only to ammonia vapors; their sensitivity was almost equal for the 30 and 90 nm thick films, and decreased significantly for the film tkness of 300 nm.