ATTs of samples S1 to S5 are higher than 80%. The highest diffuse transmittance of sample S5 is 44% at 416-nm wavelength. The diffuse transmittance decreases and total transmittance increases with increasing wavelength when the wavelength is larger than 416 nm. Sample S3 has the highest

ATT and the lowest ADT because its NRs are more vertically aligned, as shown in Figure 1. NRs in sample S5 are disordered (Figure 1e) and have more oxygen vacancies, as discussed in the PL spectra, which results in the lowest ATT and the highest ADT of sample S5. For sample S1, although the NRs are relatively ordered, the low NR density and short NR length (Figure 1a) strongly enhance the optical surface scattering [27]. As a result, sample S1 has a large diffuse transmittance. Figure 6 Total and diffuse transmittances of samples S1 to S5. BLZ945 Table

2 ATT, ADT, and SR of the AZO film and samples Sample AZO S1 S2 S3 S4 S5 ATT (%) 88.6 84.0 85.7 87.0 85.5 81.0 ADT (%) 0.4 7.3 3.2 1.5 2.8 14.2 SR (Ω/sq) 60 17 33 48 44 36 An AZO film must have a low resistance for use as a transparent conductive electrode in optoelectronic devices [16]. The electrical properties of an AZO film may be changed after thermal PF477736 price treatment JNJ-26481585 supplier at high temperature, and especially our NR growth temperature is 600°C. So, the sheet resistance (SR) of the sample was measured. The NRs at electrode positions were removed to enable good contact of the electrodes before the resistance measurement, and the results are shown in Table 2. All the sheet resistances of the samples are lower than that of the AZO film (60 Ω/sq), indicating that the electrical performance of the AZO film does not degenerate after the NR growth. We speculate that there

are two mechanisms that induce the reduction of the sheet resistances. One is that the resistance of the AZO film after the thermal treatment declines, which had been confirmed experimentally [16, 28]. The other is, as indicated in Figure 1f,g, the result of a ZnO buffer layer between NRAs and AZO film after NR growth. ZnO is naturally an n-type semiconductor due to the presence of intrinsic defects such as oxygen vacancies and zinc interstitials [29]. The resistance of a ZnO film will decline as the oxygen vacancies increase because each http://www.selleck.co.jp/products/Adrucil(Fluorouracil).html oxygen vacancy can generate two conductive electrons. The NRAs and ZnO buffer layer in sample S1 have the most oxygen vacancies, as confirmed by PL measurement, so it has the lowest sheet resistance (17 Ω/sq). Conclusions A solution-free, catalyst-free, vapor-phase growth method was used to synthesize ZnO nanorod arrays on AZO films, which were deposited on quartz substrates by RF magnetron sputtering. The sheet resistance of the sample declines after ZnO NRA growth at 600°C. TEM results show that the NRs are the single-crystal ZnO with wurtzite structure.