Self-seeded growth and ultraviolet photoresponse properties of ZnO nanowire arrays

Abstract

The authors report on the self-seeded growth of ZnO nanowire (NW) arrays on glass substrates by a simple solvothermal method using two different sol concentrations for the seed layer formation. The formations of hexagonal-shaped NWs with diameter of 20–60nm on the seed layer for 0.1M sol and mostly of trapezoidal-shaped NWs with base width of 135nm on the seed layer for 0.03M sol have been explained considering the longitudinal and transversal growths of ZnO NWs. The photocurrent behavior of ZnO NW arrays in air as well as in vacuum is analyzed in terms of adsorbed oxygen and water molecules.

Hierarchical structured ZnO nanorods on ZnO nanofibers and their photoresponse to UV and visible lights

“…It is well known that the photoresponsive phenomenon of ZnO is strongly affected by the adsorption and desorption of oxygen molecules on the surface [25][26][27][28]. When the sample is exposed to air, some oxygen molecules will be adsorbed on the surface of high surface-to-volume ratio of ZnO nanorods on the fibers increase the surface area of the system, therefore, the current increases more rapidly upon UV illumination.…”

Characterization of nano-powder grown ultra-thin film p-CuO/n-Si hetero-junctions by employing vapour-liquid-solid method for photovoltaic applications

“…In this region the number of injected electrons is very small and these are generated thermally, leading to very high electrical resistance. In region II, the current increases exponentially (I exp (cV)), where 'c' is a constant [20][21][22][23][24][25]. Hence, in the second region (0.45V <V <1.25V), the dominant transport mechanism is recombination-tunneling [20][21][22][23][24][25].…”

“…Hence, in the second region (0.45V <V <1.25V), the dominant transport mechanism is recombination-tunneling [20][21][22][23][24][25]. Finally, in region-III, the current follows a power law (I  V 2 ), indicating a space-charge limited current (SCLC) transport mechanism which is controlled by the presence of traps within the band gap of CuO [20][21][22][23][24][25]. The SCLC regime occurs when the equilibrium charge concentration is negligible compared to the injected charge concentration and this forms a space charge region near the injecting electrode.…”

“…In region II, the current increases exponentially (I exp (cV)), where 'c' is a constant [20][21][22][23][24][25]. Hence, in the second region (0.45V <V <1.25V), the dominant transport mechanism is recombination-tunneling [20][21][22][23][24][25]. Finally, in region-III, the current follows a power law (I  V 2 ), indicating a space-charge limited current (SCLC) transport mechanism which is controlled by the presence of traps within the band gap of CuO [20][21][22][23][24][25].…”

Selective zinc ion detection by functionalised ZnO nanorods with ionophore

“…6,7 ZnO nanorods are n-type semiconductors and their electrical transport is dependent on the adsorption/desorption property of surface binding chemical species. [8][9][10][11][12][13] Many onedimensional ZnO nanostructures like nanorods, nanowires, nanotubes, etc., have been synthesized by different methods and nano-devices based on these have been explored for electric field-effect switching, 14 single electron transistors, 15 biological and chemical sensing, 16 luminescence, 17 etc. The ZnO structure can be described as alternating planes made of tetrahedral coordinated O 2À and Zn 2þ ions, well-endowed alternately along the c-axis, 18 and with two crystallographic planes having opposite polarity and different surface relaxation energies.…”