Photo-Response of Functionalized Self-Assembled Graphene Oxide on Zinc Oxide Heterostructure to UV Illumination
© Fouda et al. 2016
Received: 15 October 2015
Accepted: 27 December 2015
Published: 12 January 2016
Convective assembly technique which is a simple and scalable method was used for coating uniform graphene oxide (GO) nanosheets on zinc oxide (ZnO) thin films. Upon UV irradiation, an enhancement in the on-off ratio was observed after functionalizing ZnO films by GO nanosheets. The calculations of on-off ratio, the device responsivity, and the external quantum efficiency were investigated and implied that the GO layer provides a stable pathway for electron transport. Structural investigations of the assembled GO and the heterostructure of GO on ZnO were performed using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). The covered GO layer has a wide continuous area, with wrinkles and folds at the edges. In addition, the phonon lattice vibrations were investigated by Raman analysis. For GO and the heterostructure, a little change in the ratio between the D-band and G-band was found which means that no additional defects were formed within the heterostructure.
KeywordsStructure modeling Graphene oxide on ZnO Self-assembly Raman analysis
Much attention has been attracted to the coupling of graphene oxide (GO) and graphene (GR) with some semiconductors, which makes a proper enhancement in the charge transport, photocatalytic activity, and thermal conductivity [1–4]. In particular, GO/ZnO heterostructure is desirable for the inverted structure of hybrid solar cells , transparent electrode in optoelectronic devices , photocatalytic active devices , and sensors . Zinc oxide (ZnO) has a large exciton binding energy of 59 meV, wide band gap of 3.37 eV at room temperature, piezoelectricity, catalytic activity, low cost in production, and bio-compatibility and is non-toxic (environmental friendly) and chemically stable [9, 10]. It has a wide range of applications, like transparent electrodes, gas sensors, dilute magnetic semiconductors (DMS), window layer for solar cells, active channel layer of transparent thin film transistor (TTFT), photocatalysts, surface acoustic wave devices, microsensors, and photodetectors [11, 12].
Graphene, a flat monolayer of two-dimensional (2D) honeycomb carbon atoms, has a wide range of applications due to its superior structural and electronic properties [13–15]. It can be synthesized by several methods, including micromechanical exfoliation , thermal expansion , chemical vapor deposition , and reduction from GO [19, 20]. Recently, there has been much progress in the self-assembly of nano-colloidal particles for photonics, sensors, supercapacitors, electronics, and other applications. Self-assembly technique provides a facile, rapid, inexpensive, scalable, controllable, and good way to deposit nano- and micrometer-sized particles. Controlling the interactions among particles and particle kinetics is required for device fabrication using the self-assembly method [21–23]. The colloidal composition, concentration, and system setup were considered while performing the experiment (more details about the experiment procedure can be found in the “Experimental” section).
Some studies have primarily focused on ZnO-based photodetectors [24–27]. ZnO-based nanostructured photodetectors exhibited a relatively long response time . However, building an electric field within a heterostructure junction is one of the strategies to separate and transport the photo-carriers . In the open literatures, there are some attempts to introduce GR-ZnO nano-composites, ZnO nanowires, GR arrays/films [30, 31], GR-ZnO nanorods [32, 33], and GR wrapped to hollow ZnO spheres . Moreover, resistance switching of GR to ZnO as a resistive random access memory was reported . However, the reports on the assembly of GO on ZnO films and the application of GO/ZnO heterostructure in UV sensing are still quite rare. Here, a low-cost, facile, and scalable technique was used to cover ZnO films by GO nanosheets. We used ZnO thin films as a template for GO to improve the separation efficiency of photo-generated electron hole pairs upon UV irradiation. This hybrid heterostructure exhibited a repeated fast and uniform response to UV illumination because of the high-transport properties of carbon nanostructures.
Structural characterizations were performed using X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), and Raman spectroscopy. Burker-D8 diffractometer with Cukα radiation was used for XRD measurements. The surface morphology was investigated using FE-SEM (Helios 400). The nano-scale structures were monitored using transmission electron microscopy (model JEM 1230, JEOL, Japan). The characterizations were extended to the lattice vibration modes by micro-Raman spectroscopy measurements at room temperature (model Renishaw System 2000) with Ar+ laser at wavelength of 514 nm and power of 3 mW. To evaluate the photoconductivity of the samples, a patterned mask was used to deposit 20-nm-thick Al electrodes (4 mm wide) by thermal evaporation technique as shown in Fig. 1. I-V characteristics were measured at room temperature by a Keithley electrometer (model 6517B). A UV source (254 nm) with power density of 250 mW cm−2 was used to irradiate the samples.
Representative XRD patterns of graphite, ZnO films, and GO on ZnO films are shown in Fig. 2d. For ZnO films on an a-plane sapphire substrate, a well-oriented (0002) ZnO peak can be observed beside the reflexes of the substrate. In the inset of Fig. 2d, the symmetric nature, sharpness of the (0002) peak with full width at half maximum (FWHM) of 0.087°, and the absence of reflections from other planes confirm a good c-axis orientation perpendicular to the (11–20) plane of the sapphire substrate. The distinct sharp (002) peak of graphite was observed at 2θ of 26.55°. After exfoliation, the (002) peak is shifted to a lower angle for GO nanosheets on ZnO films which is related to the increase in the inter-planar spacing beside the reflections of ZnO films and the substrate.
Surface functionalization of ZnO films by the GO layer was conducted by self-assembly technique. ZnO films act as a good template for the deposited GO layer because of its smoothness. It is worth noting that we emphasized the enhancement in the UV photo-response performance for GO/ZnO heterostructure with respect to ZnO films. Since GO creates two-dimensional electronic-conducting channels for the photo-generated carriers, separation and transport of photo-generated electron hole pairs and reducing the recombination improve the on-off ratio.
Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.
- Liu W, Cai J, Li Z (2015) Self-assembly of semiconductor nanoparticles/reduced graphene oxide (RGO) composite aerogels for enhanced photocatalytic performance and facile recycling in aqueous photocatalysis. ACS Sustainable Chem Eng 3(2):277–5View ArticleGoogle Scholar
- Gao N, Fang X (2015) Synthesis and development of graphene-inorganic semiconductor nanocomposites. Chem Rev 115(16):8294–46View ArticleGoogle Scholar
- Yang M-Q, Zhang N, Pagliaro M, Xu Y-J (2014) Artificial photosynthesis over graphene-semiconductor composites. Are we getting better? Chem Soc Rev 43:8240–14View ArticleGoogle Scholar
- Xing M, Shen F, Qiu B, Zhang J (2014) Highly dispersed boron doped graphene nanosheets loaded with TiO2 nanoparticles for enhancing CO2 photoreduction. Sci Rep 4:6341–7View ArticleGoogle Scholar
- Park H, Chang S, Jean J, Jayce J, Cheng J, Araujo PT et al (2013) Graphene cathode-based ZnO nanowire hybrid solar cells. Nano Lett 13:233–6View ArticleGoogle Scholar
- K Hasan, MO. Sandberg, O Nur, M Willander. Transparent electrodes: ZnO/polyfluorene hybrid LED on an efficient hole-transport layer of graphene oxide and transparent graphene electrode. Adv. Opt. Mater. 2014; 2(4): 304: doi:https://doi.org/10.1002/adom.201470021.
- Pan X, Yang MQ, Xu Y-J (2014) Morphology control defect engineering and photoactivity tuning of ZnO crystals by graphene oxide-a unique 2D macromolecular surfactant. Phys Chem Chem Phys 16:5589–10View ArticleGoogle Scholar
- Biroju RK, Tilak N, Rajender G, Dhara S, Giri PK (2015) Catalyst free growth of ZnO nanowires on graphene and graphene oxide and its enhanced photoluminescence and photoresponse. Nanotechnol 26:145601–12View ArticleGoogle Scholar
- Look DC, Hemsky JW, Sizelove JR (1999) Residual native shallow donor in ZnO. Phys Rev Lett 82:2552View ArticleGoogle Scholar
- Jagadish C, Pearton S (2006) Zinc oxide bulk, thin films and nanostructures. Elsevier Ltd., Oxford, Ox5 1GB, UKGoogle Scholar
- Shinde SS, Rajpure KY (2012) Fabrication and performance of N-doped ZnO UV photoconductive detector. J Alloys Compd 522:118–4View ArticleGoogle Scholar
- Gonzalez Vallsa I, Lira Cantu M (2009) Vertically-aligned nanostructures of ZnO for excitonic solar cells: a review. Energy Environ Sci 2:19–34View ArticleGoogle Scholar
- Morozov SV, Novoselov KS, Geim AK (2008) Giant intrinsic carrier mobilities in graphene and its bilayer. Phys Rev Lett 100:16602–2View ArticleGoogle Scholar
- Castro Neto AH, Guinea F, Peres NMR, Novoselov KS, GeimAK (2009) The electronic properties of graphene. Rev Mod Phys 81:109–55Google Scholar
- Rani A, Nam SW, Park M (2010) Electrical conductivity of chemically reduced graphene powders under compression. Carbon Lett 11(2):90–5View ArticleGoogle Scholar
- Schniepp H, Li J, Aksay I (2006) Functionalized single graphene sheets derived from splitting graphite oxide. J Phys Chem B(110):8535–4View ArticleGoogle Scholar
- Novoselov K, Geim A, Morozov SV, Jiang D, Zhang Y, Dubonos SV, Grigorieva IV, Firsov AA (2004) Electric field effect in atomically thin carbon films. Science 306:666–3View ArticleGoogle Scholar
- Duraia E-SM, Mansurov Z, Tokmoldin S (2011) Formation of graphene by the thermal annealing of a graphite layer on silicon substrate in vacuum. Vac 86:232–2View ArticleGoogle Scholar
- Fouda AN, Abu Assy M, El Enany G, Yousf N (2014) Enhanced capacitance of thermally reduced hexagonal graphene oxide for high performance supercapacitor. Fullerenes Nanotubes Carbon Nanostruct 23:618–4View ArticleGoogle Scholar
- Fouda AN, Abu-Assy MK, Yousf N (2014) Structural and capacitive characterizations of high temperature nitrogen annealed graphene oxide. IOSR J Appl Phys 6(2):33–4View ArticleGoogle Scholar
- Liberman V, Yilmaz C, Bloomstein TM, Somu S, Echegoyen Y, Busnaina A et al (2010) A nanoparticle convective directed assembly process for the fabrication of periodic surface enhanced Raman spectroscopy substrates. Adv Mater 22:4298–4View ArticleGoogle Scholar
- Velev OD, Gupta S (2009) Materials fabricated by micro- and nanoparticle assembly-the challenging path from science to engineering. Adv Mater 21:1897–9View ArticleGoogle Scholar
- Prevo BG, Kuncicky DM, Velev OD (2007) Engineered deposition of coatings from nano- and micro-particles: a brief review of convective assembly at high volume fraction. Colloids Surf A Physicochem Eng Asp 311:2–8View ArticleGoogle Scholar
- Wang ZL, Song JH (2006) Piezoelectric nanogenerators based on zinc oxide nanowire arrays. Science 312:242–4View ArticleGoogle Scholar
- Inamdar SI, Rajpure KY (2014) High-performance metal-semiconductor-metal UV photodetector based on spray deposited ZnO thin films. J Alloys Compd 595:55–4View ArticleGoogle Scholar
- Young S-J, Liu Y-H, Hsiao C-H, Chang S-J, Wang B-C, Kao T-H, Tsai K-S, San-Lein W (2014) ZnO-based ultraviolet photodetectors with novel nanosheet structures. IEEE Trans Nanotechnol 13(2):238–7View ArticleGoogle Scholar
- Li QH, Gao T, Wang YG, Wang TH (2005) Adsorption and desorption of oxygen probed from ZnO nanowire films by photocurrent measurements. Appl Phys Lett 86(12):123117View ArticleGoogle Scholar
- Park C, Lee J, Sob H-M, Chang WS (2015) An ultrafast response grating structural ZnO photodetector with back-to-back Schottky barriers produced by hydrothermal growth. J Mater Chem C 3:2737–6View ArticleGoogle Scholar
- Qiao H, Yuan J, Xu Z, Chen C, Lin S, Wang Y et al (2015) Broadband photodetectors based on graphene–Bi2Te3 heterostructure. ACS Nano 9(2):1886–8View ArticleGoogle Scholar
- Liu H, Sun Q, Xing J, Zheng Z, Zhang Z, Lu Z, Zhao K (2015) Fast and enhanced broadband photoresponse of a ZnO nanowire array/reduced graphene oxide film hybrid photodetector from the visible to the near-infrared range. ACS Appl Mater Interfaces 7(12):6645–6View ArticleGoogle Scholar
- Chang H, Sun Z, Ho KY-F, Tao X, Yan F, Kwok W-M, Zheng Z (2011) A highly sensitive ultraviolet sensor based on a facile in situ solution-grown ZnO nanorod/graphene heterostructure. Nanoscale 3:258–6View ArticleGoogle Scholar
- Boruah BD, Ferry DB, Mukherjee A, Misra A (2015) Few-layer graphene/ZnO nanowires based high performance UV photodetector. Nanotechnol 26:235703–7View ArticleGoogle Scholar
- Fu X-W, Liao Z-M, Zhou Y-B, Wu H-C, Bie Y-Q, Xu J, Yu D-P (2012) Graphene/ZnO nanowire/graphene vertical structure based fast-response ultraviolet photodetector. Appl Phys Lett 100:223114–4View ArticleGoogle Scholar
- Khoa NT, Kim SW, Yoo D-H, Cho S, Kim EJ, Hahn SH (2015) Fabrication of Au/graphene-wrapped ZnO-nanoparticle-assembled hollow spheres with effective photo-induced charge transfer for photocatalysis. ACS Appl Mater Interf 7(6):3524–8Google Scholar
- Lin C-L, Chang W-Y, Huang Y-L, Juan P-C, Wang T-W, Hung K-Y et al (2015) Resistance switching behavior of ZnO resistive random access memory with a reduced graphene oxide capping layer. Jap J Appl Phys 54:04DJ–08Google Scholar
- Fouda AN, Duraia E-SM, Eid EA (2014) Ultra-smooth and lattice relaxed ZnO thin films. Superlattice Microstruct 73:268–6View ArticleGoogle Scholar
- Eid EA, Fouda AN (2015) Influence of homo buffer layer thickness on the quality of ZnO epilayers. Spectrochim Acta Part A 149:127–5View ArticleGoogle Scholar
- Rasuli R, Iraji zad A (2010) Density functional theory prediction for oxidation and exfoliation of graphite to grapheme. Appl Surf Sci 256:7596–3View ArticleGoogle Scholar
- Liu L, Lu W, Gao J, Chen Z (2012) Amorphous structural models for graphene oxides. Carbon 50:1690–8View ArticleGoogle Scholar
- Wang L, Lee K, Sun YY, Lucking M, Chen Z, Zhao J, Zhang S (2009) Graphene oxide as an ideal substrate for hydrogen storage. ACS Nano 3:2995–5View ArticleGoogle Scholar
- Yan JA, Xian LD, Chou MY (2009) Structural and electronic properties of oxidized graphene. Phys Rev Lett 103(8):086802View ArticleGoogle Scholar
- Tamura R (2010) Conductance of telescoped double-walled nanotubes from perturbation calculations. Phys Rev B 82:035415View ArticleGoogle Scholar
- Beall G, Duraia E-SM, Yu Q, Liu Z (2014) Single crystalline graphene synthesized by thermal annealing of humic acid over copper foils. Physica E 56:331–5View ArticleGoogle Scholar
- Duraia E-SM, Beall G (2015) Humidity sensing properties of reduced humic acid. Sens Actuators B 220:22–4View ArticleGoogle Scholar
- Ming-Lung T, Sua Y-K, Ma CY (2006) Nitrogen-doped p-type ZnO films prepared from nitrogen gas radio-frequency magnetron sputtering. J Appl Phys 100:053705–4View ArticleGoogle Scholar
- Yahia SB, Znaidi L, Kanaev A, Petitet JP (2008) Raman study of oriented ZnO thin films deposited by sol-gel method. Spectrochim Acta Part A 71:1234–4View ArticleGoogle Scholar
- Wermelinger T, Borgia C, Solenthaler C, Spolenak R (2007) D-Raman spectroscopy measurements of the symmetry of residual stress fields in plastically deformed sapphire crystals. Acta Mater 55:4657–8View ArticleGoogle Scholar
- Jia W, Yen WM (1989) Raman scattering from sapphire fibers. J Raman Spectros 20:785–3View ArticleGoogle Scholar
- Shen J, Hu Y, Li C, Qin C, Shi M, Ye M (2009) Layer-by-layer self-assembly of graphene nanoplatelets. Langmuir 25:6122–6View ArticleGoogle Scholar
- Yin S, Men X, Sun H, She P, Zhang W, Wu C et al (2015) Enhanced photocurrent generation of bio-inspired graphene/ZnO composite films. J Mater Chem A 3:12016–6View ArticleGoogle Scholar
- Wang Z, Zhan X, Wang Y, Muhammad S, Huangb Y, He J (2012) A flexible UV nanosensor based on reduced graphene oxide decorated ZnO nanostructures. Nanoscale 4:2678–6View ArticleGoogle Scholar
- Boruah BD, Mukherjee A, Sridhar S, Misra A (2015) Highly dense ZnO nanowires grown on graphene foam for ultraviolet photodetection. ACS Appl Mater Interf 7(19):10606–6View ArticleGoogle Scholar
- Xia FN, Mueller T, Lin YM, Valdes-Garcia A, Avouris P (2009) Ultrafast graphene photodetector. Nat Nanotechnol 4:839–4View ArticleGoogle Scholar