三色碳纳米管场发射灯的研制

报道了以粉末状碳纳米管为原料用丝网印刷法制备图形化的碳纳米管阴极的技术。采用热处理和氢等离子体表面处理方法提高了丝网印刷法制备的碳纳米管阴极的场发射性能，处理后阴极的阈值场强从4V／μm降到～1V／μm，场发射电流密度在4．5V／μm时达到了2．53mA／μm^2，发射点密度从～10^3／cm^3增加到～10^5／cm^2。在此基础上，成功地设计和封装了三极管结构的三色高亮度碳纳米管场发射灯器件。     

三色碳纳米管场发射灯的研制

报道了以粉末状碳纳米管为原料用丝网印刷法制备图形化的碳纳米管阴极的技术.采用热处理和氢等离子体表面处理方法提高了丝网印刷法制备的碳纳米管阴极的场发射性能,处理后阴极的阈值场强从4V/μm降到～1V/μm,场发射电流密度在4.5V/μm时达到了2.53mA/cm2,发射点密度从～103/cm2增加到～105/cm2.在此基础上,成功地设计和封装了三极管结构的三色高亮度碳纳米管场发射灯器件.     

三色碳纳米管场发射灯的研制

报道了以粉末状碳纳米管为原料用丝网印刷法制备图形化的碳纳米管阴极的技术.采用热处理和氢等离子体表面处理方法提高了丝网印刷法制备的碳纳米管阴极的场发射性能,处理后阴极的阈值场强从4V/μm降到～1V/μm,场发射电流密度在4.5V/μm时达到了2.53mA/cm2,发射点密度从～103/cm2增加到～105/cm2.在此基础上,成功地设计和封装了三极管结构的三色高亮度碳纳米管场发射灯器件.     

丝网印刷碳纳米管阴极老炼特性研究

影响碳纳米管阴极场发射稳定性和寿命的主要因素有真空度、场发射过程中的热效应以及场发射体对场发射电流的承载能力等。本文从外部特性的角度，对丝网印刷碳纳米管阴极老炼前后的场发射特性曲线进行了分析，得出了经过老炼后场强增强因子减小而有效发射面积比增大的变化规律，而且老炼电压越高，这种变化越大。这一结果与实验中发光图像的观察结果很好得吻合，说明经过老炼后，碳纳米管有效场发射点变钝而有效场发射点数量增加。     

四针状氧化锌/碳纳米管复合阴极的制备及其场发射性能研究

采用丝网印刷技术制备四针状氧化锌(tetrapod-liked zinc oxide nanoneedles, T-ZnO)场发射阴极, 通过向T-ZnO阴极表面电泳沉积碳纳米管(carbon nanotube, CNT)薄膜制备了T-ZnO/CNT复合阴极。扫描电子显微镜观察表明: 与T-ZnO阴极相比, T-ZnO/CNT复合阴极与衬底电极之间具有较大的有效接触面积。采用二极场发射器件结构研究T-ZnO和T-ZnO/CNT的场发射特性, 实验表明: 相对于T-ZnO阴极, T-ZnO/CNT复合阴极发射电流密度大、开启场强与阈值场强低、发射点密度高, 且具有良好的工作稳定性。     

一种有效提高CNTs/CNFs阴极场发射性能的热处理方法

报道了一种新的提高碳纳米管／碳纳米纤维（CNTs／CNFs）丝网印刷阴极场发射性能的后处理方法。利用化学气相沉积（CVD）方法制备的CNTs／CNFs作为阴极材料,采用丝网印刷工艺在玻璃基板上制备场发射阴极,在H2和C2H2混合气氛下500℃处理20min,能有效提高其场发射性能,改善场发射显示器的发光均匀性。热处理后的阴极开启电压从2．4V降低到1．8V,在电场为3．9V／μm时,电流密度从0．02mA／cm^2提高到0．50mA／cm^2,发光点密度提高了近4个数量级。场发射特性的提高主要是由于热处理使阴极表面出现了大量突出并互相间有一定间距的CNTs／CNFs,这种形貌非常有利于电子场发射。     

电流法改善碳纳米管阴极场发射特性

针对丝网印刷碳纳米管阴极,提出电流法进行表面后处理,有效改善碳纳米管阴极场发射特性.利用扫描电子显微镜表征电流法处理前后CNTs阴极表面形貌变化,并对处理前后CNTs阴极进行场发射特性测试.结果表明,电流法处理后CNTs阴极表面残留有机物被破坏,开启电场从2.4 V/μm降低到1.6 V/μm,同样面积的薄膜(印制面积为1 cm×1 cm)在2.6 V/μm场强下的发射电流由30 μA提高到了800 μA,说明电流处理对于提高薄膜的场发射特性有明显作用.该方法在碳纳米管场发射显示器的制作中具有很好的实际应用价值.     

大面积碳纳米管冷阴极的制备与研究

针对碳纳米管(CNT)阴极场发射均匀性这一关关键难题，根据CNT场发射理论制备了一种新型碳纳米管阴极印刷浆料，实验表明：质量分数约为20％的纯化CNT与4．2％的导电氧化物粘接材料混合形成的印刷浆料，其阴极具有较佳的发射均匀特性，用丝网印刷技术制作成的大面积(对角线长度大于12．5cm)阴极，再经过快速烧结技术及两步后处理工艺，既能除掉粘接材料又能使CNT很好地与衬底固定，并使碳纳米管部分直立和充分暴露，进一步改善了发射均匀性，该均匀发射的阴极开启场为2．0V／μm在电场强度阴极可望应用于场致发射显示器，液晶显示的背光源、电光源等器件。     

电解液法改善碳纳米管阴极场发射特性

针对丝网印刷碳纳米管(CNT)阴极,提出用电解液法进行表面后处理,有效改善碳纳米管阴极场发射特性.利用扫描电子显微镜表征电解液法处理前后CNT阴极表面形貌变化,并对处理前后CNT阴极进行场发射特性测试.结果表明,电解液法处理后有更多的CNT伸出有机浆料表面,开启电场从2.4 V/μm降低到1.4 V/μm,同样面积的薄膜(印制面积为1 cm×1 cm)在3.0 V/μm场强下的发射电流由100μA提高到了1 800μA,说明电解液处理对于提高薄膜的场发射特性有明显作用.该方法在碳纳米管场发射显示器的制作中具有很好的实际应用价值.     

碳纳米管场发射器件新型阴极的研究

碳纳米管场发射显示器件（CNT-FFDs）中阴极的制备和表面处理一直是其中的关键环节而备受关注,本文通过光刻技术、丝网印刷技术、表面超声等流程制作带有平整电阻层的发射阴极,并对该阴极进行场发射测试,并通过扫描电镜（SEM）照片分析阴极表面,发现开启电场、发射均匀性及电流稳定性比以前未加处理的阴极有很大程度上的改善。此法适合于大面积的碳纳米管场发射显示的阴极制作。     

An empirical study of dynamic properties of an individual carbon nanotube electron source system

In this paper we present an empirical study of some dynamic properties of an individual carbon nanotube (CNT) field emission electron source system. We propose a circuit model that represents the CNT cathode to anode diode as a capacitor in parallel with a voltage-controlled variable resistor. The transient response of the CNT electron source system to the falling edge of a voltage step input was evaluated. For input voltages below the threshold voltage for field emission, the nanotube loop is effectively open and the circuit response is consistent with a discharging capacitor. On the other hand, for input voltages above field emission threshold, the nanotube loop conducts and now the capacitor discharges to a certain extent through the nanotube loop as well. Field emission current versus voltage data also shows that the resistance across the CNT cathode to anode diode varies as a function of applied voltage. Below turn-on voltage, the diode behaves as an open circuit (4 TΩ at the ammeter noise floor). Above turn-on voltage, resistance falls exponentially, as expected from the Fowler–Nordheim equation for cold field emission current. Experimental current–voltage data is presented for a simple emitter array consisting of two CNTs with equal lengths. Despite the similarity in their lengths the turn-on voltages of the nanotubes varied significantly, viz. 26 V versus 109 V. This large difference in the turn-on voltages can be attributed to tip imperfections. For advanced array applications such as high-throughput parallel e-beam lithography, in which precise dose control is necessary, the diode circuit model will be useful for controlling individually addressed nanotubes to account for dissimilar field emission properties. The model may also be applied to optimize the design of a SEM incorporating a single CNT electron source.     

Ultralow-voltage boron-doped diamond field emitter vacuum diode

A boron-doped diamond field emitter diode with ultralow turn-on voltage and high emission current is reported. The diamond field emitter diode structure with a built-in cap was fabricated using molds and electrostatic bonding techniques. The emission current versus anode voltage of the capped diamond emitter diode with boron doping, sp² content, and vacuum thermal electric (VTE) treatment shows a very low turn-on voltage of 2 V. A high emission current of 1 μA at an anode voltage of less than 10 V can be obtained from a single diamond tip. The turn-on voltage is significantly lower than comparable silicon field emitters     

Drain-voltage dependence of IGFET turn-on voltage

The turn-on voltage (or threshold voltage) characteristic of an enhancement-type insulated-gate field-effect transistor (IGFET) in its pentode operation region, is analyzed based on a simple model. A new definition for the turn-on voltage at just-saturated state is given and a new simple formula for the turn-on voltage shift in IGFETs pentode operation region, is deduced. This assumes a reduction of gate-induced bulk charge under the influence of the drain voltage. Agreement of the theory with experiment is good.     

Low turn-on voltage field emission triodes with selective growth ofcarbon nanotubes

A low turn-on voltage, field emission triode array has been fabricated using the selective deposition of carbon nanotubes (CNTs) in a microwave plasma chemical vapor deposition (MPCVD) system. The field emission triodes exhibited a low turn-on voltage of 13 V and a large emission current of 23 μA with the gate voltage at 60 V. Short-term stress reveals a 10% current fluctuation within 1800 sec. The excellent electric properties suggest that the array shows potential for application in field emission displays and vacuum microelectronics     

Field-emission enhancement of Mo-tip field-emitted arrays fabricated by using a redox method

This work has improved the emission characteristics for Mo-tips of field-emitter array (FEA) through a reduction-oxidation (redox) process. The maximum emission current of the 1600 tips array significantly increased from 23.2 /spl mu/A to 2.36 mA with the turn-on voltage decreasing from 70 V to 48 V after the redox treatment. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) indicate that the main factor improving electron field emission characteristics for the Mo-tips is the increase in enhancement factor (/spl beta/) and, possibly, number of emission sites of Mo films.     

In-situ vacuum-sealed lateral FEAs with low turn-on voltage andhigh transconductance

We have fabricated a new lateral field emitter array, in-situ vacuum-sealed, which exhibits a low turn on voltage and a high transconductance value without any additional vacuum sealing process. The vacuum-sealed lateral FEA (VLFEA) is encapsulated during the fabrication process, so that field emission characteristics can be measured without any additional vacuum environments. Experimental current-voltage (I-V) characteristics show that the anode current is field emission current obeying the linearity of the Fowler-Nordheim (F-N) plot. The experimental turn-on voltage of about 9 V is in good agreement with the extracted one from the F-N plot. In order to verify the integrity of the vacuum sealed micro-cavity, we have measured the anode current of the VLFEA both in a high vacuum chamber and in an atmospheric environment and found that the structure is well sealed. The anode currents as a function of gate voltage of the Mo-sealed VLFEA are analyzed and transconductance is extracted. The experimental results show that the VLFEA has superior field emission characteristics, such as low turn-on voltage and high transconductance, and does not require any additional troublesome vacuum sealing     

A new lateral field emission device using chemical-mechanicalpolishing

A polysilicon lateral field emission device using chemical-mechanical polishing (CMP) is proposed and experimental results on the first prototype are reported. In this method, dry oxidation process determines the interelectrode gap. Thus, it is relatively easy to form electrode gaps with dimensions less than 1 μm. Also, the process allows for good uniformity and reproducibility in controlling the interelectrode gap. The turn-on voltage of the fabricated device with interelectrode gap of 3500 Å is as low as 5.4 V and the emission current is as high as 9 μA at 9.3 V. From the Fowler-Nordheim (FN) equation, field emitting area (α) and field enhancement factor (β) are estimated to explain the low turn-on voltage and the high emission current. The emission current fluctuation is about ±4% for 25 min     

关于雪崩结开启电压和关断电压差别的研究

本文详细研究了雪崩结导通电压和关断电压的差别。 当结特征尺度在微米量级时,这个差别将不能忽略, 这个结果与现有报道不一致,并且对对器件参数的正确表征有较大影响。 实验发现当结面积变小时, 这个差别将增大。 本文对该现象进行了分析, 给出了理论解释,认为这个现象是由于结导通的阈值增益随着结面积的减小而增加的缘故。在雪崩渐近电流公式中, 所谓的“击穿电压”实际上应该是雪崩结关断电压。 修正了传统的关于雪崩渐近电流和盖革模式雪崩光电二极管的增益公式。     

双栅肖特基源漏MOSFET的阈值电压模型

通过求解泊松方程得到了双栅肖特基势垒MOSFET的解析模型. 这个解析模型包括整个沟道的准二维电势分布和适用于短沟双栅肖特基势垒MOSFET的阈值电压模型.数值模拟器ISE DESSIS验证了模型结果.     

双栅肖特基源漏MOSFET的阈值电压模型

通过求解泊松方程得到了双栅肖特基势垒MOSFET的解析模型. 这个解析模型包括整个沟道的准二维电势分布和适用于短沟双栅肖特基势垒MOSFET的阈值电压模型.数值模拟器ISE DESSIS验证了模型结果.