- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
[IEEE 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Kyoto, Japan (2018.7.9-2018.7.13)] 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Electron sources based on diamond pin-diodes
摘要： Efficient electron sources are of ongoing interest in particular for space and terrestrial power telecommunications and radar applications. With conventional cathode technology based on thermionic- and field electron emission a novel approach for direct electron emission is realized through a diamond pin diode. Electrons injected into the conduction band of the intrinsic layer of the diode can be released into vacuum with a negative electron affinity surface of the i-layer. The diamond pin diodes were prepared on boron doped (p-type) substrates with (111) surface orientation. A high purity intrinsic and a phosphorus doped diamond layer (n-type, ~400nm thickness) were deposited in dedicated PECVD systems, respectively. An additional contact layer comprised of nanostructured carbon was grown in a dedicated PECVD. The layered device was processed by lithography utilizing an aluminum hard mask to etch mesa structures with diameters ranging from 50μm to 200μm. The final devices were treated in a pure hydrogen plasma to induce the negative electron affinity properties of the i-layer. After an annealing step in high vacuum individual pin diodes were biased in forward current and voltages up to 20V. The observation of light from the diode was attributed to the UV exciton state and indicated bipolar transport. At a diode current of about 80mA an electron emission current of 25μA was observed from a single 200μm diameter diode.
关键词： Diamond,solid state electronics,doping,phosphorus,electron emission,plasma-enhanced chemical vapor deposition,nanostructured carbon,pin diode,single crystal
更新于2025-09-23 15:21:21
-
Insights into the Role of Plasma in Atmospheric Pressure Chemical Vapor Deposition of Titanium Dioxide Thin Films
摘要： In this work, the effect of plasma on the chemistry and morphology of coatings deposited by Atmospheric Pressure Plasma Enhanced Chemical Vapor Deposition (AP-PECVD) is investigated. To do so, plasma deposited amorphous titanium dioxide (TiO2) thin films are compared to thin films deposited using Atmospheric Pressure Chemical Vapor Deposition (AP-CVD) not involving the use of plasma. We focus here on the effect and the interest of plasma in the AP-PECVD process over AP-CVD for low substrate temperature deposition. The advantages of AP-PECVD over AP-CVD are often suggested in many articles however no direct evidence of the role of the plasma for TiO2 deposition at atmospheric pressure was reported. Hence, herein, the deposition via both methods is directly compared by depositing coatings with and without plasma using the same CVD reactor. Through the control of the plasma parameters, we are able to form low carbon coatings at low temperature with a deposition rate twice faster than AP-CVD, clearly showing the interest of plasma. Plasma enhanced methods are promising for the deposition of coatings at industrial scale over large surface and at high rate.
关键词： AP-PECVD,TiO2 thin films,Atmospheric Pressure Chemical Vapor Deposition,Atmospheric Pressure Plasma Enhanced Chemical Vapor Deposition,plasma,AP-CVD,low substrate temperature deposition
更新于2025-09-23 15:21:01
-
Enhancement for Potential-Induced Degradation Resistance of Crystalline Silicon Solar Cells via Anti-Reflection Coating by Industrial PECVD Methods
摘要： The issue of potential-induced degradation (PID) has gained more concerns due to causing the catastrophic failures in photovoltaic (PV) modules. One of the approaches to diminish PID is to modify the anti-re?ection coating (ARC) layer upon the front surface of crystalline silicon solar cells. Here, we focus on the modi?cation of ARC ?lms to realize PID-free step-by-step through three delicate experiments. Firstly, the ARC ?lms deposited by direct plasma enhanced chemical vapor deposition (PECVD) and by indirect PECVD were investigated. The results showed that the ef?ciency degradation of solar cells by indirect PECVD method is up to ?33.82%, which is out of the IEC 62804 standard and is signi?cantly more severe than by the direct PECVD method (?0.82%). Next, the performance of PID-resist for the solar cell via indirect PECVD was improved signi?cantly (PID reduced from ?31.82% to ?2.79%) by a pre-oxidation step, which not only meets the standard but also has higher throughput than direct PECVD. Lastly, we applied a novel PECVD technology, called the pulsed-plasma (PP) PECVD method, to deal with the PID issue. The results of the HF-etching rate test and FTIR measurement indicated the ?lms deposited by PP PECVD have higher potential against PID in consideration of less oxygen content in this ?lm. That demonstrated the ?lm properties were changed by applied a new control of freedom, i.e., PP method. In addition, the 96 h PID result of the integrated PP method was only ?2.07%, which was comparable to that of the integrated traditional CP method. In summary, we proposed three effective or potential approaches to eliminate the PID issue, and all approaches satis?ed the IEC 62804 standard of less than 5% power loss in PV modules.
关键词： solar cell,potential-induced degradation,anti-re?ection coating,plasma enhanced chemical vapor deposition
更新于2025-09-23 15:21:01
-
Nucleation and growth dynamics of graphene grown through low power capacitive coupled radio frequency plasma enhanced chemical vapor deposition
摘要： We present the study on graphene growth on Cu substrate through low power capacitive coupled radio frequency (RF) plasma enhanced chemical vapor deposition. Fully-covered graphene was grown on Cu substrate through a plasma composed of various argon/methane/hydrogen gas ratio with a 50 W RF power source within a minute under a relatively low substrate temperature at 850 +C. The nucleation and growth dynamics is further investigated through processing and analysis of the images acquired through scanning electron microscopy, and interpreted with a modi?ed Johnson-Mehl-Avrami-Kolmogorov model. The roles of hydrogen in limiting the nucleation density and stabilization of the graphene grain edges are discussed in light of the analysis, and a time dependent grain expansion rate in which the graphene grains grow fast at the early stage and saturated at later stage is implemented into the model to achieve good ?tting of the coverage evolution.
关键词： Johnson-Mehl-Avrami-Kolmogorov model,Plasma enhanced chemical vapor deposition,Growth dynamics,Graphene,Nucleation
更新于2025-09-19 17:13:59
-
Suppression of Parasitic Epitaxy Growth and Realization of High-Quality Wafer Surface Passivation of Silicon Heterojunction Solar Cells
摘要： Intrinsic hydrogenated amorphous silicon (i-a-Si:H) ?lms lead to excellent surface passivation of crystalline silicon wafers. However, a-Si:H deposition on a crystalline silicon wafer often results in undesired epitaxy growth, which deteriorates the passivation property, In this paper, we studied the in?uence of varying plasma enhanced chemical vapor deposition (PECVD) parameters, such as the product of the gas pressure (P ) and the electrode distance (Di) and the hydrogen dilution ratio (R = SiH4/(H2 + SiH4) × 100), on the passivation quality and the properties of silicon heterojunction (SHJ) solar cells. Measurements showed that proper combinations of high P ×Di and large R values can yield high minority carrier lifetimes (MCLTs) of passivated silicon wafers. Also, the tendency of MCLTs measured from passivated wafers is the same as that for open circuit voltages (Voc) of fabricated SHJ solar cells. A high Voc is obtained from SHJ solar cells when unwanted epitaxial growth is minimized at the wafer surface.
关键词： Plasma-enhanced chemical-vapor deposition,Amorphous semiconductors,Silicon solar cells,Heterojunctions
更新于2025-09-19 17:13:59
-
Inserting dome shape microstructure for enhancement of ultraviolet photodetector performance of n-ZnO nanorods/p-Si heterojunction
摘要： A mixed intermediate layer of silica and zinc oxide (SZO) with architecturally dome-shaped microstructure is fabricated and characterized by combining a hydrothermal method and a plasma-enhanced chemical vapor deposition technique. Our results demonstrated that 200 (cid:1)C was an optimum deposition temperature for dome shape architecture SZO layer, acting as an antire?ection layer in the ultraviolet range and buffer layer for growth ZnO nanorods (NRs) arrays. Consequently, at 2.0 V reverse bias, the photo-to-dark current ratio measured with an p-Si/n-ZnONRs photodiode employing the dome-shaped SZO layer is improved by almost three orders of magnitude in the ultraviolet range as compared to that under visible-light illumination.
关键词： ZnO nanorods,Hydrothermal growth,Plasma-enhanced chemical vapor deposition,Photodiodes
更新于2025-09-16 10:30:52
-
Broadband UV-assisted thermal annealing of low- <i>k</i> silicon carbonitride films using a C-rich silazane precursor
摘要： Low-k dielectric silicon carbonitride (SiCxNy) films are deposited by plasma-enhanced chemical vapor deposition using a carbon-rich silazane precursor, N-methyl-aza-2,2,4-trimethylsilacyclopentane (SiC7NH17), at 100 °C. The post-treatments of SiCxNy films are carried out by thermal annealing and a broadband UV-assisted thermal annealing (UV-annealing) at 400 °C for 5 min. Compared to the thermal annealing treatment, UV-annealing can improve both dielectric and mechanical properties of low-k SiCxNy films. Under thermal annealing, SiCxNy films show great thermal stability, but little structural change. In contrast, upon UV-annealing, most of the Si–H and N–H bonds are broken up, which induces more Si–N cross-linking and converts Si–C matrix into Si–N matrix. The ethylene bridges in Si–(CH2)2–Si also remain intact, but the unbridged hydrocarbons in Si–(CH2)2–N and Si–CH2–CH3 bonds decompose completely during the UV-annealing process. These account for the reduced dielectric constant to k = 3.2 from 3.6 and a 21% enhancement of Young’s modulus to 7.4 GPa in the SiCxNy films after UV-annealing. Broadband UV-annealing shows promise as a post-treatment method for enhancing the properties of low-k dielectric barrier, SiCxNy films.
关键词： low-k dielectric,silicon carbonitride,UV-assisted thermal annealing,plasma-enhanced chemical vapor deposition,mechanical properties
更新于2025-09-10 09:29:36
-
Effects of gas residence time of CH <sub/>4</sub> /H <sub/>2</sub> on sp <sup>2</sup> fraction of amorphous carbon films and dissociated methyl density during radical-injection plasma-enhanced chemical vapor deposition
摘要： Quadruple mass spectrometric measurements of CH3 density during radical-injection plasma-enhanced chemical vapor deposition to consider the sp2 fraction of amorphous carbon (a-C) films were performed. The sp2 fraction of the a-C films reached a minimum of 46%, where the CH3 density was maximum for a residence time of 6 ms. The sp2 fraction of the a-C films was tailored with the gaseous phase CH3 density during the deposition. This knowledge is useful for understanding the formation mechanism of bonding structures in the a-C films, which enables the precise control of their electronic properties.
关键词： CH3 density,sp2 fraction,radical-injection plasma-enhanced chemical vapor deposition,amorphous carbon films,gas residence time
更新于2025-09-04 15:30:14