**4. Conclusions**

In conclusion, the VCl4 is successfully employed as a new ALD precursor to grow a VO2 film on the Si (100) substrate. Besides, without any postannealing process required, the as-deposited VO2 film is directly crystallized and provides a significant SMT property. Moreover, it can be reasonably imagined that the VCl4 can be used not only to grow crystalline VO2 films, but also to grow other different vanadium oxides (VO*x*, *x* = 2) by controlling the ALD-process parameters (such as process temperature, VCl4/H2O ratio, and so forth). It is just like this that the VCl4 had been used as a precursor for atmospheric pressure CVD to grow different vanadium oxides (VO2 and V2O5) by controlling process parameters of temperature and VCl4/H2O ratio [30–32]. We anticipate this work to be a starting point for using VCl4 as a precursor to grow various directly crystallized vanadium oxides by ALD without any postannealing process.

**Supplementary Materials:** The following are available online at http://www.mdpi.com/2079-6412/8/12/431/s1, Part 1: A brief report provided by Bruker Corporation for explaining "Why Si (113) peak appears in GIXRD profile?" Part 2: Full temperature-dependent Raman spectra of the VO2 films. Figure S1: Raman spectra of the VO2 film measured at indicant temperature for heating cycle (temperature from 30 to 80 ◦C), Figure S2: Raman spectra of the VO2 film measured at indicant temperature for cooling cycle (temperature from 78 to 35 ◦C).

**Funding:** This research was funded by the Ministry of Science and Technology of Taiwan (Nos.: MOST 105-2221-E-153-001 and MOST 106-2221-E-153-004).

**Acknowledgments:** The authors would like to thank Dr. Ya-Ching Yang (Bruker Corporation) for discussing and providing a brief report to explain "Why Si (113) peak appears in GIXRD profile?", Ms. Hui-Jung Shih (Instrument Center, NCKU) for HR-SEM analysis, Ms. Mei-Lan Liang and Ms. Shih-Wen Tseng (Center for Micro/Nano Science and Technology, NCKU) for FIB and TEM analyses, and Ms. Swee-Lan Cheah (Instrument Center, NTHU) for HR-XPS analysis.

**Conflicts of Interest:** The authors declare no conflict of interest.
