The conduction mechanisms in dielectric films are crucial to the successful applications of dielectric materials. There are two types of conduction mechanisms in dielectric films, that is, electrode-limited conduction mechanism and bulk-limited conduction mechanism. The electrode-limited conduction mechanism depends on the electrical properties at the electrode-dielectric interface. Based on this type of conduction mechanism, the physical properties of the barrier height at the electrode-dielectric interface and the effective mass of the conduction carriers in dielectric films can be extracted. The bulk-limited conduction mechanism depends on the electrical properties of the dielectric itself. According to the analyses of bulk-limited conduction mechanisms, several important physical parameters in the dielectric films can be obtained, including the trap level, the trap spacing, the trap density, the carrier drift mobility, the dielectric relaxation time, and the density of states in the conduction band. In this paper, the analytical methods of conduction mechanisms in dielectric films are discussed in detail.

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Metal-oxide-semiconductor capacitors that incorporate La2O3 dielectric films were deposited by radio frequency magnetron sputtering. In this work, the essential structures and electrical properties of La2O3 thin films were investigated. Capacitance–voltage, energy dispersive x-ray spectrometry, and transmission electron microscopy analyses reveal that an interfacial layer was formed, subsequently reducing the effective dielectric constant of the 700°C annealed La2O3 thin films. The dominant conduction mechanism of the Al∕La2O3∕p-Si metal-lanthanum oxide-semiconductor capacitor is space-charge-limited current from 300to465K in the accumulation mode. Three different regions, Ohm’s law region, trap-filled-limited region, and Child’s law region, were observed in the current-density–voltage (J–V) characteristics at room temperature. The activation energy of traps calculated from the Arrhenius plots was about 0.21±0.01eV. The electronic mobility, trap density, dielectric relaxation time, and density of states in the conduction band were determined from the space-charge-limited conduction at room temperature.

Metal-oxide-semiconductor capacitors incorporating HfO2 dielectrics were fabricated and investigated. In this work, the structural and electrical characterizations were performed at the interfaces of HfO2∕Si and Al∕HfO2, respectively. The physical analyses reveal that an interfacial layer of Hf-silicate between 700°C-annealed HfO2 and Si was formed. The dominant conduction mechanisms of the Al∕HfO2∕p-Si structure are the Schottky emission at high temperatures (≳465K) and low electric fields (≲2.2MV∕cm) and the Fowler-Nordheim tunneling at low temperature (77K) and high electric fields (≳2.6MV∕cm), respectively. The electron effective mass in HfO2 and the barrier height at the Al∕HfO2 interface are evaluated using both the intercept of the Schottky plot and the slope of the Fowler-Nordheim plot. Therefore, the barrier height at the Al∕HfO2 interface was determined to be about 0.94eV. The electron effective masses in HfO2 are 0.4m0 and 0.09m0 for the effective oxide thickness (EOT)=6nm and EOT=3.15nm, respectively.

The melt mixing technique was used to prepare various polypropylene (PP)‐based (nano)composites. Two commercial organoclays (denoted 20A and 30B) served as the fillers for the PP matrix, and two different maleated (so‐called) compatibilizers (denoted PP‐MA and SMA) were employed as the third component. The results from X‐ray diffraction (XRD) and transmission electron microscope (TEM) experiments revealed that 190 °C was an adequate temperature for preparing the nanocomposites. Nanocomposites were achieved only if specific pairs of organoclay and compatibilizer were simultaneously incorporated in the PP matrix. For example, PP/20A(5 wt %)/PP‐MA(10 wt %) and PP/30B(5 wt %)/SMA(5 wt %) composites exhibited nanoscaled dispersion of 20A or 30B in the PP matrix. Differential scanning calorimetry (DSC) results indicated that the organoclays served as nucleation agents for the PP matrix. Generally, their nucleation effectiveness increased with the addition of compatibilizers. The thermal stability enhancement of PP after adding 20A was confirmed with thermogravimetric analysis (TGA). The enhancement became more evident as a suitable compatibilizer was further added. However, for the 30B‐included composites, thermal stability enhancement was not evident. The dynamic mechanical properties (i.e., storage modulus and loss modulus) of PP increased as the nanocomposites were formed; the properties increment corresponded to the organoclay dispersion status in the matrix. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 4139–4150, 2004

Preparing super-tough and heat-resistant PLLA/elastomer blends by constructing stereocomplex crystallites at the interface to simultaneously tailor interface and matrix properties.

In this work, bipolar resistive switching characteristics were demonstrated in the Pt/ZnO/Pt structure. Reliability tests show that ac cycling endurance level above 106 can be achieved. However, significant window closure takes place after about 102 dc cycles. Data retention characteristic exhibits no observed degradation after 168 h. Read durability shows stable resistance states after 106 read times. The current transportation in ZnO films is dominated by the hopping conduction and the ohmic conduction in high-resistance and low-resistance states, respectively. Therefore, the electrical parameters of trap energy level, trap spacing, Fermi level, electron mobility, and effective density of states in conduction band in ZnO were identified.