甲基丙烯酸—磷脂酰乙醇甲基丙烯酰胺共聚物LB膜的研究

制备了不同摩尔比的甲基丙烯酸-磷脂酰乙醇甲基丙烯酰胺共聚物,研究了这种共聚物在水面的表面压力(π)-分子面积(A)曲线、共聚物制成的MOS LB膜的电容(C)-电压(V)特性及此LB膜的相变温度。     

Interface traps contribution to capacitance of Al2O3/(GaN)AlGaN/GaN heterostructures at low frequencies

Influence of interface traps at Al₂O₃/(GaN)/AlGaN interface on low and high frequency capacitance of Al₂O₃/(GaN)/AlGaN/GaN heterostructure capacitor was studied. New features were observed in the capacitance curves. Obtained experimental results were modeled and simulated and accordance with the experiment has been obtained. For lower frequencies a new capacitance peak in the depletion and increase of the capacitance in a plateau region were measured. The capacitance peak in the depletion region was successfully explained by a capacitance response of the interface traps with U-shape density distribution. On the other hand the increase of the capacitance plateau was modeled by the homogeneous interface trap distribution. We assume that the traps located near the band edges having the highest density are able to respond to the low frequency measuring.     

Fabrication and electrical characterization of nickel/p-Si Schottky diode at low temperature

In this study the current–voltage and capacitance–voltage characteristics of metal semiconductor Ni/p-Si(100) based Schottky diode on p- type silicon measured over a wide temperature range (60–300 K) have been studied on the basis of thermionic emission diffusion mechanism and the assumption of a Gaussian distribution of barrier heights. The parameters ideality factor, barrier height and series resistance are determined from the forward bias current–voltage characteristics. The barrier height for Ni/p-Si(100) Schottky diode found to vary between 0.513 eV and 0.205 eV, and the ideality factor between 2.34 and 8.88 on decreasing temperature 300–60 K. A plot involving the use of ϕ_b versus 1/T data is used to gather evidence for the occurrence of a Gaussian distribution of barrier height and obtain the value of standard deviation. The observed temperature dependences of barrier height and ideality factor and non-linear activation energy plot are attributed to the Gaussian distribution of barrier heights at the metal-semiconductor contact. The barrier height of Ni/p-Si(100) Schottky diode was also measured over wide temperature from the capacitance-voltage study.     

C-V Characterization of α-Fe2O3/Block-Copolymer Composite Particulate Films

α-Fe2O3 nanocrystal was encapsulated by a block-copolymer, hydroxylated poly(styrene-b-butadiene-styrene)(HO-SBS) to fabricate composite microspheres with α-Fe2O3 cores and HO-SBS shell. Its film fabricated on n-Si wafer acts as the insulator layer in the metal-insulator-semiconductor(MIS) structure. The capacitance-voltage(C-V) properties were measured to characterize the composite particulate films.     

硅量子点中电子的荷电动力学特征

利用频率依赖电容谱的测量,对于SiO₂/硅量子点/SiO₂/硅衬底隧 穿电容中硅量子点的荷电特征进行了研究.由于量子点的极小尺寸和良好的均匀性,室温下 在强反型区成功地观察到了与单电子隧穿相关的两个电容和电导共振峰,它们分别对应于硅 衬底导带上的电子与量子点中第一与第二个基态之间直接隧穿过程.实验数据分析给出了量 子点中的库仑荷电能,并进行了讨论. 关键词： 量子点 电容谱 库仑荷电能 直接隧穿     

Domain configuration and dielectric properties of Ba0.6Sr0.4TiO3 thin films

The microstructure and electrical properties of Ba_0.6Sr_0.4TiO₃ thin films have been investigated. Nanometer-sized domains, ranging from 8 to about 30 nm, were observed by piezoresponse force microscopy (PFM). The critical size, below which only single domains exist, is found to be about 31 nm. The film exhibits ferroelectric behavior characterized by polarization hysteresis loop and capacitance-voltage curve.     

A model for the electrical characteristics of metal-ferroelectric-insulator-semiconductor field-effect transistor

An improved theoretical model on the electrical characteristics of metal-ferroelectric-insulator-semiconductor field-effect transistor (MFIS-FET) has been proposed by considering the history-dependent electric field effect and the mobility model. The capacitance-voltage (C-V) characteristics of MFIS structure is evaluated by combining the switching physics of ferroelectric with the silicon physics, and the drain current-gate voltage (I_D-V_GS) and drain current-drain voltage (I_D-V_DS) characteristics of MFIS-FET are modeled by combining the switching physics of ferroelectric with Pao and Sah’s double integral. For two MFIS-FETs with SrBi₂Ta₂O₉ and (Bi,La)₄Ti₃O₁₂ ferroelectric layers, the C-V, I_D-V_GS and I_D-V_DS characteristics are simulated by using the improved model, and the results are more consistent with the previous experiment than those based on Lue model, indicating that the improved model is suitable for simulating the electrical characteristics of MFIS-FET. This work is expected to provide some guidance to the design and performance improvement of MFIS structure devices.