Appl Phys Lett 2001, 78:1391–1393.CrossRef Competing interests The authors declare that they have no competing interests. Authors’ contributions BR fabricated the investigated devices and performed the numerical simulation. The experimental work was done by BR and HK. Data analysis and manuscript conception were done by SM and BR. SM supervised the experimental work, and NB was the project supervisor. AE contributed to the discussion of the results and the writing of the manuscript. All authors read and approved

the final manuscript.”
“Background In recent years, strong attentions have been paid in the growth of semiconductor nanostructures on graphene [1–5] for electronic and optoelectronic applications. Nanostructures such as nanowires, nanorods, nanoneedles, MDV3100 molecular weight ZD1839 nanosheets, and nanowalls can offer additional functionality to graphene for realizing advanced nanoscale applications in photovoltaics, nanogenerators, field emission devices, sensitive biological and chemical sensors, and efficient energy conversion and storage devices [6–8]. This is due to the superb properties of nanostructures such as high aspect ratio, extremely large surface-to-volume ratio, and high porosity [6–10]. Graphene has a great potential for novel electronic devices because of its extraordinary electrical, thermal, and mechanical properties, including carrier mobility exceeding 104 cm2/Vs and a thermal conductivity

of 103 W/mK [11–14]. Therefore, with the excellent

electrical and thermal characteristics of graphene layers, growing semiconductor nanostructures on graphene layers would enable their novel physical properties to be exploited in diverse sophisticated device applications. Graphene is a 2D hexagonal network of carbon atoms which is formed by making strong triangular σ-bonds of the sp 2 hybridized orbitals. This bonding structure is similar to the (111) plane of zinc-blende structure and C plane of a hexagonal crystalline structure. With this regard, the growth of semiconductor nanostructures and thin films on graphene is feasible. Recently, there are several works on the growth and application of graphene/semiconductor nanocrystals that show desirable combinations of these Cell press properties not found in the individual components [15–20]. The 1D zinc oxide (ZnO) semiconducting nanostructures are considered to be important multifunctional building blocks for fabricating various nanodevices [21, 22]. Since graphene is an excellent conductor and transparent material, the hybrid structure of ZnO/graphene shall lead to several device applications not only on Si substrate but also on other insulating substrates such as transparent glass and transparent flexible plastic. Owing to the unique electronic and optical properties of ZnO nanostructures, such hybrid structure can be used for sensing devices [23–25], UV photodetector [26], solar cells [27], and light-emitting diodes [28].