Xiaomei Qin

Highly-ordered silicon inverted nanocone arrays with broadband light antireflectance

In this work, highly-ordered silicon inverted nanocone arrays are fabricated by integration of nanosphere lithography with reactive ion etching (RIE) method. The optical characteristics of as-prepared Si inverted nanocone arrays are investigated both by experiments and simulations. It is found that the Si nanocone arrays present excellent broadband light antireflectance properties, which are attributed to the gradient in the effective refractive index of nanocones and enhanced light trapping owing to optical diffraction. The inverted Si nanocone arrays might find a variety of applications in solar cells and photodetectors.

The enhanced superconductivity of Cu-1234 under high pressure

The evolution of superconducting transition of CuBa2Ca3Cu4O10+δ (i.e. Cu-1234) superconductor has been studied by using diamond anvil cell technique. The Tc of Cu-1234 can be enhanced continuously from ambient reaching to 123 K at 15 GPa. This seems the one more system besides Hg-12(n-1)n which demonstrate the positive pressure effect on Tc over a wide pressure range above 10 GPa.

THE SYNTHESIS OF INFINITE-LAYER CaCuO2 AND HYPOTHETICAL p-TYPE DOPING WITH Na UNDER HIGH-PRESSURE

The CaCuO2 with infinite-layer structure (IL CaCuO2) was synthesized under high-pressure. The p-type doped infinite layer compounds Ca1-xNaxCuO2 with the different carriers concentration (x=0.05, 0.1) were also prepared from high temperature and high-pressure technique. The lattice parameter a decreases with increasing Na content x in the p-type doped Ca1-xNaxCuO2, suggesting that the hole like carriers enter into the CuO2 plane, and Na is successfully doped into the infinite-layer CaCuO2. This was confirmed by the systematic evolution of resistance with increasing the doping level. However, no superconductivity was observed in the samples.

Preparation and Properties of Aluminum-doped ZnO–SiO2 Composite Thin Films

Aluminum-doped ZnO (AZO) thin films are usually used as transparent conductors. For practical applications, however, the relatively high refractive index of AZO can lead to high optical reflection. In this work, we modified the optical properties of AZO thin films by adding different amounts of SiO2 into the AZO thin films to prepare the AZO-SiO2 composite thin films. The AZO-SiO2 films were deposited on quartz substrates using a co-sputtering deposition method. It was shown that the refractive index of the AZO-SiO2 thin films consistently decreased with the amount of SiO2 contained in the films. In the meantime, the resistivity of the AZO-SiO2 thin films was found to increase with the SiO2 content in the films. The effects of the deposition conditions on the optical and electrical properties of the AZO-SiO2 thin films were systematically investigated.