Investigation of External Charges Effects on Piezoelectric ZnO Nanogenerator

Authors Samira Fathi, Tahereh Fanaei Sheikholeslami

Electronic Department, Faculty of Electrical and Computer Engineering, University of Sistan and Baluchestan, Zahedan, Iran

Issue Volume 8, Year 2016, Number 2
Dates Received 15 March 2016; revised manuscript received 12 June 2016; published online 15 July 2016
Citation Samira Fathi, Tahereh Fanaei Sheikholeslami, J. Nano- Electron. Phys. 8 No 2, 02047 (2016)
DOI 10.21272/jnep.8(2).02047
PACS Number(s) 81.07.Gf, 85.50. – n
Keywords Free charge carrier, Mechanical energy harvesting, Piezoelectric nanogenerator, Piezoelectric potential, Surface charge density, ZnO nanowire.
Annotation Piezopotential generation in semiconductive ZnO nanowire (NW), oriented along the c-axis [0001], is significantly affected by free charge carriers within the ZnO NW. In this paper, the effect of free carriers’ distribution in semiconductive ZnO nanowire is investigated, using a Finite Element Method (FEM). The mentioned effect leads to modification of the conduction band variation, carrier concentration profiles, and eventually, the magnitude and distribution of the piezoelectric potential. The impact of free charge carriers shows that the negative potential distributed at the tip of ZnO NW is decreased from V = – 270 mv for the donor concentration ND = 1 × 1015 C/m3 to the V = – 25 mV, in presence of the donor concentration of ND = 1 × 1018 C/m3. With selecting the appropriate electrical boundary conditions and applying the surface charges density at the top of the nanowire, the potential reduction is compensated. The electrostatic effect leads to a significant enhancement of the piezoelectric potential. The results are well shown the interplay of volume and surface charges and their influence on performance of nanogenerator, and so are crucial for designing of nanogenerators with high piezoelectric potential and good efficiency.

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