VietNam 2013 

IXth Rencontres du Vietnam
Quy-Nhon, August 4-10, 2013

 QNplage

 Nanophysics: from fundamentals to applications

(the return)

 

Wednesday 7
Nems, molecules

› 16:10 - 16:30 (20min)
Enlarged Crystalline Grain in Sputtered Anatase Nb-Doped TiO2 Thin Films by Suppressing Voids in Amorphous Precursors
Ngoc Lam Huong Hoang  1@  , Shoichiro Nakao  2@  , Yasushi Hirose  3@  , Tetsuya Hasegawa  3@  , Naoomi Yamada  4@  
1 : Nano and Energy Center  (NEC)
5F, T2 Buliding, VNU University of Science, 334 Nguyen Trai, Hanoi. -  Vietnam
2 : Kanagawa Academy of Science and Technology  (KAST)
Kawasaki 213-0012 -  Japan
3 : Department of Chemistry, The University of Tokyo
Tokyo 113-0033 -  Japan
4 : Department of Applied Chemistry, Chubu University
Kasugai 487-8501 -  Japan

In this study, we show that suppression of void in amorphous precursor is essential to obtain large grain anatase Nb-doped TiO2 (TNO) thin films. We have systematically investigated relation between microstructures of amorphous precursors and grain size of TNO films after annealing as a function of working pressure (Pw) during sputter deposition. We found that the microstructures of the amorphous precursors can be classified into two groups: dense amorphous fabricated at Pw < 1 Pa and pours amorphous with many voids fabricated at Pw ≥ 1 Pa. TNO films with very large grains of approximately 50 m (micrometre) were obtained from the dense precursors, whereas the porous precursors yielded TNO films with small grain size less than 10 m (micrometre). The suppression of the voids were achieved not only by low Pw deposition but also by filtering the obliquely incident components. We found, however, significant suppression of the electrical properties of TNO films deposited at low Pw due to sputter damage caused by the high energy particle bombardment. Alternatively, deposition at high Pw with filtering the obliquely incident components might be a suitable method for dense films with reduced sputter damage.


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