High-resolution transmission electron microscopy (HRTEM) micrographs of the samples buy CB-839 were taken using a JEOL 2010 HRTEM (JEOL Ltd., Tokyo, Japan). A PerkinElmer Lambda 750 UV/VIS/NIR spectrometer (PerkinElmer, Waltham, MA, USA) was employed to obtain the optical transmission, reflectance, and absorbance of the samples. The optical reflectance spectra were measured at an incident angle of 45° to the samples. Electrical properties of the samples were studied using a Keithley Source Measure Unit 236 (Keithley Instruments, Inc.,

Cleveland, OH, USA) for current-voltage (I-V) measurement. Prior to the I-V measurement, gold electrodes (in circular shape, Stattic diameter of about 2 mm) were evaporated on top of the sample using a thermal evaporator. The distance between two consecutive electrodes was fixed at 2 mm. Results and discussion Figure 1a shows the FESEM images of the In2O3 NPs formed by the evaporation of In wires in a N2O plasma environment. A high density of NPs with an average size of approximately 40 ± 9 nm was found to be randomly distributed on the quartz substrate. A magnified FESEM image (Figure 1b) reveals the appearance of the NPs. Structures with different numbered

facets (three, four, five, six, and eight faces) corresponding to triangular, rhombohedral, pentagonal, hexagonal, and octahedral shapes, respectively, can be recognized from the sample. These structures indicate that the In2O3 NPs formed are in crystalline state. The observed In and O signals from the energy-dispersive X-ray (EDX) spectrum (Figure 1c) confirm selleck compound the composition of the In2O3 NP. The Si signal that PIK-5 appeared in the EDX spectrum originated from the quartz substrate. The color of the In2O3 NPs changed from white to yellowish upon thermal radiation treatment (Additional file 1: Figure S2). The films appear to be more transparent after the treatment. The FESEM image depicted in Figure 1d reveals a compact nanostructured

film for the sample after undergoing thermal radiation treatment. The sizes of the nanostructures vary largely from 60 to 300 nm. Meanwhile, we observed that the nanostructures mainly consist of shapes with fewer facets which are triangular or rhombohedral (Figure 1e). The EDX spectrum taken from the nanostructured films (Figure 1f) showed high signals of In and O, reflecting high purity of the nanostructured In2O3 films formed by this technique. The signal of the substrate (Si) was largely suppressed due to the closely packed structure of the In2O3 film, which limited the emission of X-ray from the substrate atoms after the thermal radiation treatment. Figure 1 FESEM images and EDX spectra. FESEM images of (a, b) as-grown In2O3 NPs and (d, e) thermal radiation-treated In2O3 NPs. (c, f) EDX spectra of the as-grown In2O3 NPs and thermal radiation-treated In2O3 NPs, respectively.