Comparative study of the electrical properties of diamond films grown by microwave plasma assisted and hot-filament chemical vapor deposition

Schottky diodes were built on different polycrystalline diamond films grown by Microwave Plasma and Hot Filament Chemical Vapor Deposition and their electrical properties were studied. The barrier height increased with the diamond film quality and the corresponding ideality factor decreased. Even though the lower-quality HFCVD film displayed poor rectifying properties, it was found to be much less sensitive to variations in the operating conditions (air vs. vacuum). The activation energies of the films depend on morphological parameters, as preferable grain size or orientation. The bulk conduction also depends on the quality of the deposited films, changing from ohmic to trap-free or shallow trap SCLC and SCLC with an exponential distribution of traps. The hypothesis of using the electrical measurements as an indicator for film quality has been discussed.     

Optical and electronic property tailoring by MoS2-polymer hybrid solar cell

The ternary blend system such as binary donor and an acceptor or binary acceptor and a donor offers a way to improve the power conversion efficiency of the polymer solar cells (PSCs) by enhancing optical properties and electrical properties. In this work, PTB7, PC₇₁BM and Molybdenum disulfide nano-sheet (MoS₂NS) ternary blend system were investigated as an active material for OPV. The optimized ternary blend system showed increment of 17% power conversion efficiency (PCE) from 6.98% to 8.18%. The origin of improved PCE mainly arises from the significant increment in J_SC and marginal change in V_OC and FF. This improved PCE is due to increased light harvesting and improved charge carrier mobility in the active matrix. The marginal enhancement in V_OC and FF was correlated with the density of trap states (DOS) obtained from capacitance measurement of the device. The optical absorption and energy transfer mechanism of the ternary blend film is explained by absorption and photoluminescence measurement respectively. Further, the conversion efficiency due to improved charge carrier transport was described by modified SCLC mobility measurements for electron and hole only devices. The obtained result suggests that presence of MoS₂NS along with PTB7:PC₇₁BM binary system play dual role like an improved charge transport layer as well as light harvesting.     

BST薄膜漏电流温度特性研究

采用射频溅射制备Ba0.8Sr0.2TiO3(BST)薄膜,研究了测试温度(295～375K)对BST薄膜J-V(电流密度-电压)特性的影响.实验发现:J∝Vm在低场下(V＜1.8V)m≈1,高场下(V＞1.8V)m≈8.随着测试温度升高,在低场下电流密度增大,指数m值保持不变;而在高场下电流密度减小,指数m值减小.通过进一步分析发现:电流密度和温度的关系在低场下满足lnJ∝-1T,在高场下满足logJ∝1t.     

基于空间电荷限制对有机材料空穴迁移率的测定

利用空间电荷限制电流的方法测定有机材料的空穴迁移率。用SCLC方法测试得到NPB,m-MTDATA,CBP,Balq四种有机材料的空穴零场迁移率,拟合绘制出四种材料在不同电场下空穴的场依赖迁移率。测试不同浓度红色磷光染料Ir(piq)2acac)掺杂到这四种母体后空穴迁移率的变化情况,分析发现,掺杂母体与客体的能级匹配是研究载流子在掺杂层输运模式的关键,其直接决定了有机材料空穴迁移率的大小。     

Estimation of electron mobility of n-doped 4, 7-diphenyl-1, 10-phenanthroline using space-charge-limited currents

The electron mobilities of 4, 7-diphenyl-1, 10-phenanthroline (BPhen) doped 8-hydroxyquinolinatolithium (Liq) at various thicknesses (50-300 nm) have been estimated by using space-charge-limited current measurements. It is observed that the electron mobility of 33 wt% Liq doped BPhen approaches its true value when the thickness is more than 200 nm. The electron mobility of 33 wt% Liq doped BPhen at 300 nm is found to be ～5.2 × 10~(-3) cm~2/(V·s) (at 0.3 MV/cm) with weak dependence on electric field, which is about one order of magnitude higher than that of pristine BPhen (3.4 × 10~(-4) cm~2/(V·s)) measured by SCLC. For the typical thickness of organic light-emitting devices, the electron mobility of doped BPhen is also investigated.     

用空间电荷限制电流法测定n型掺杂的BPhen的电子迁移率

摘 要 用空间电荷限制电流（SCLC）法测定了不同厚度（50-300nm）的Liq掺杂BPhen的电子迁移率。实验结果表明在33wt％Liq掺杂的BPhen中,当厚度达到150nm以后电子迁移率接近于体材料的迁移率。对于300nm厚的掺杂的BPhen,测定的电子迁移率约为5.4×10-3 cm2/Vs （电场强度为0.3MV/cm时）,比本征BPhen的迁移率（3.4×10-4 cm2/Vs）高约一个数量级,而且其迁移率基本上不依赖于电场。同时还对掺杂的BPhen为有机电致发光器件（OLED）的典型厚度时的电子迁移率进行了测定。     

Sol-gel法制备SrTiO_3薄膜的电阻开关性能研究

采用sol-gel法制作了28nm厚的SrTiO3薄膜和Au/SrTiO3/LaNiO3/Si(100)三明治结构的器件,并研究其物理性能。结果显示:室温下,用直流电压可以使薄膜的电阻在高低阻态间进行转换。最大的电阻变化率约为10309。对I-V特性的分析,发现在高阻态时,有空间电荷限制电流机制(SCLC)和肖特基势垒导电机制存在。应用在高场区有非对称电子陷阱中心的空间电荷限制电流理论,解释了这种电阻开关现象。     

BET-Inhibitor I-BET762 and PARP-Inhibitor Talazoparib Synergy in Small Cell Lung Cancer Cells

Small cell lung cancer (SCLC) is an aggressive type of lung cancer with high mortality that is caused by frequent relapses and acquired resistance. Despite that several target-based approaches with potential therapeutic impact on SCLC have been identified, numerous targeted drugs have not been successful in providing improvements in cancer patients when used as single agents. A combination of targeted therapies could be a strategy to induce maximum lethal effects on cancer cells. As a starting point in the development of new drug combination strategies for the treatment of SCLC, we performed a mid-throughput screening assay by treating a panel of SCLC cell lines with BETi or AKi in combination with PARPi or EZH2i. We observed drug synergy between I-BET762 and Talazoparib, BETi and PARPi, respectively, in SCLC cells. Combinatorial efficacy was observed in MYCs-amplified and MYCs-wt SCLC cells over SCLC cells with impaired MYC signaling pathway or non-tumor cells. We indicate that drug synergy between I-BET762 and Talazoparib is associated with the attenuation HR-DSBR process and the downregulation of various players of DNA damage response by BET inhibition, such as CHEK2, PTEN, NBN, and FANCC. Our results provide a rationale for the development of new combinatorial strategies for the treatment of SCLC.     

Space–charge‐limited conduction in vacuum‐deposited PVDF films

Current–voltage characteristics of poly(vinylidene fluoride) (PVDF) films fabricated on glass substrates by thermal evaporation technique in the metal–polymer–metal sandwich configuration were studied. The vacuum‐deposited PVDF films were predominantly of α form. However, when subjected to high‐voltage, short‐duration singular pulse, it possibly resulted in mixed α + β form. The I–V curves of such films display the low‐field ohmic region and the high‐field square‐law region. The current versus thickness curves in the square‐law region and the transition voltage, V_tr, versus thickness curves indicate the conduction process to be space–charge‐limited. The analyses of the current–voltage characteristics indicated the presence of uniformly distributed high‐trapping carrier densities on the order of 10²⁴ m⁻³ eV⁻¹ with average activation energy of 0.263 eV. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 1347–1354, 1999     

Bi_4Ti_3O_（12）铁电薄膜的I－V特性测量及导电机理

Ｂｉ＿４Ｔｉ＿３Ｏ＿（１２）薄膜是一种具有广泛应用前景的典型的铁电薄膜。本文报道了用ＭＯＣＶＤ方法制备的Ｂｉ＿４Ｔｉ＿３Ｏ＿（１２）薄膜的Ｉ－Ｖ特性测量及其导电机理。结果表明，在低场下，Ｂｉ＿４Ｔｉ＿３Ｏ＿（１２）薄膜的Ｉ－Ｖ特性表现为欧姆性质，在中强场下，薄膜的导电机理遵从ＳＣＬＣ理论。