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Modulating the water pulse time during thermal atomic layer deposition is an effective approach to enhancing the ferroelectric properties of undoped HfO 2 thin films. Through grazing incidence X-ray diffraction (GI-XRD), it was observed that a shorter water pulse time can inhibit formation of the monoclinic phase and thereby obtain good remanent polarization. Transmission electron microscopy (TEM) images and GIXRD analysis were used to reveal the crystallization conditions of the undoped HfO 2 thin films. By modulating the water pulse time during deposition of all samples, no impurities were found in these films via X-ray photoelectron spectroscopy. Moreover, samples with shorter water pulse times revealed lower binding energy and higher leakage current. However, electric measurement results of samples with shorter water pulse times revealed a higher remanent polarization of approximately 9 μC cm −2 and a coercive field of ∼1.95 MV cm −1 compared with other samples. After endurance testing, the films lasted for more than 10 8 cycles at 2.25 V, so they are ideally suited to low-power ferroelectric CMOS devices and nonvolatile memory applications.

Highly Nano-porous SiO2-ZrO2 aerogels were manufactured with tetraethylorthosilicate (TEOS) and zirconyl nitrate dihydrate (ZrO(NO3)2 .5H2O) by the sol-gel method followed by supercritical drying technique. The prepared aerogels are performed by SEM, FT-IR and BET to characterize and analyze the morphology and pore structure of SiO2-ZrO2 aerogels. The results showed that:(i) The areogels are the typical of nano pores in the interval between 1<Dp<30 nm; (ii) the specific surface areas varied from 300 to 620 m2/g with (SBET)MAX = 615.5 m2/g with 35wt% Zirconia and the surface areas decreased with the increase of zirconia; The thermal conductivity attains 0.015 W/(m.k) ; (iii) a mass of Si-O-Zr bands existed in the aerogels indicating a homogeneous distribution of the components on the nano scale.

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