“…ZnO is an important II-VI semiconductor, have been extensively studied in photovoltaics [15,16], photoelectrochemical cells [17], UV detectors [18] , lasers [19], light emitting diodes [20] and gas sensors [21] , due to its unique optical and electrical properties including wide band gap, higher excitonic binding energy, superior electron mobility, low cost, and environmental friendliness. On the other hand, carbon nanotube has many remarkable electrical and physical properties including high carrier transport mobility [22,23], high mechanical strength [24] and excellent chemical stability.…”