In this paper, we show that Eu silicate can be fabricated by optimizing the Eu2O3/Si multilayer nanostructure deposited on Si substrates. Both the structural and optical properties of nanostructures are studied in detail. Through precisely controlling the thickness of Eu2O3 and Si layer at nanometer scale, the Eu silicate with highly efficient room-temperature (RT) light emission associated to Eu2+ ions is obtained after annealing in N2 atmosphere.

Methods The Eu2O3 /Si multilayer films with five periods were grown on Si substrates at 400°C by RF magnetron sputtering. The thin films were deposited in 3.0-mTorr Ar atmosphere. The Eu2O3 layer and Si layer were prepared by alternately sputtering the Eu2O3 target and Si target. The thickness of Eu2O3 layers was kept the same in all samples, while the thickness of Si layers was varied in different samples, as shown in Table 1. After deposition, the samples were thermally treated at 1,000°C for 30 s in Caspase inhibitor N2 ambient by rapid thermal annealing. Transmission electron microscopy (TEM, Tecnai G2 F20 S-Twin, FEI Company, Hillsboro, OR, USA) was conducted to investigate the samples’ morphology. The distribution of elements selleck inhibitor in the film was detected by scanning TEM (STEM), and crystallization

was demonstrated by selected area electron diffraction pattern (SAED). Rutherford backscattering spectrometry (RBS) was carried out to investigate the film composition. The samples’ crystalline phases were identified by X-ray diffraction (XRD, D/max 2400, Rigaku Corporation, Tokyo, Japan) measurements. RT photoluminescence (PL) and photoluminescence excitation (PLE) measurements were performed by using a spectrofluorometer (Nano Log, HORIBA Ltd., Minami-Ku, Kyoto, Japan) equipped with a 450-W Xe lamp. Table 1 Eu 2 O 3 /Si multilayer structure Sample Thickness of Eu2O3layer (nm) Thickness of Si layer (nm) 1 5 8 2 5 17 3 5 25 4 5 42 Results and discussion The cross-sectional TEM images of as-deposited sample

GPX6 are shown in Figure 1a,b. The film thickness is about 150 nm, with 5 nm in the Eu2O3 layer and 25 nm in the Si layer in one period. The interface between Eu2O3 and Si is very sharp and clear. Moreover, multicrystalline Si has formed in Si layers in the as-deposited sample, which has also been confirmed by SAED, as shown in Figure 1c. The interplanar spacing (d) is about 3.11 Å from the radius of the primary diffraction ring, which agrees with the d of the Si (111) plane. We think that the high substrate temperature and the Eu2O3 layer may induce Si crystallization. Figure 1 Cross-sectional TEM images of as-deposited sample 3. (a) Full view of the film, (b) partial enlarged view of the film, and (c) the SAED image of the film. Figure 2a,b shows the TEM cross section of the sample with a Si layer thickness of about 25 nm after annealing at 1,000°C for 30 s in N2 ambient. The interfaces between Eu2O3 layers and Si layers became blurry. This indicates that the strong reaction between Eu2O3 and Si has happened.