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In situ Photoluminescence Study of Plasma Effects on Passivation of Crystalline Silicon Coated with Aluminum Oxide
摘要: A degradation of crystalline silicon surface passivation provided by aluminum oxide (Al2O3) is generally observed after plasma processes, e.g., deposition of amorphous silicon nitride. To minimize such detrimental effect, a better understanding of the interaction between plasma species and the Al2O3 layer is required. Using in situ photoluminescence, the passivation quality of as-deposited and annealed crystalline silicon wafers coated with Al2O3 grown by atomic layer deposition is characterized in real time during argon-hydrogen plasma exposure. The photoluminescence intensity of as-deposited samples instantly steps up after the plasma ignition, and then it gradually decreases as a function of plasma exposure time. However, only degradation of photoluminescence signal can be found if the samples are annealed prior to the plasma treatment. The interaction between vacuum UV light from plasma and different types of chemical bonds in the Al2O3 layer is proposed to explain the obtained results. Understanding the mechanisms and root cause leading to different behavior between as-deposited and annealed samples under plasma exposure is a first step toward redesigning the process flow for better surface passivation.
关键词: in situ photoluminescence,plasma exposure,aluminum oxide,surface passivation
更新于2025-09-23 15:23:52
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Elucidating the Exceptional Passivation Effect of 0.8 nm Evaporated Aluminium on Transparent Copper Films
摘要: Slab-like copper films with a thickness of 9 nm (~70 atoms) and sheet resistance of ≤9 Ω sq?1 are shown to exhibit remarkable long-term stability toward air-oxidation when passivated with an 0.8 nm aluminium layer deposited by simple thermal evaporation. The sheet resistance of 9 nm Cu films passivated in this way, and lithographically patterned with a dense array of ~6 million apertures per cm2, increases by <3.5% after 7,000 h exposure to ambient air. Using a combination of annular-dark field scanning transmission electron microscopy, nanoscale spatially resolved elemental analysis and atomic force microscopy, we show that this surprising effectiveness of this layer results from spontaneous segregation of the aluminium to grain boundaries in the copper film where it forms a ternary oxide plug at those sites in the metal film most vulnerable to oxidation. Crucially, the heterogeneous distribution of this passivating oxide layer combined with its very low thickness ensures that the underlying metal is not electrically isolated, and so this simple passivation step renders Cu films stable enough to compete with Ag as the base metal for transparent electrode applications in emerging optoelectronic devices.
关键词: passivation,thin film,transparent electrode,lithography,copper
更新于2025-09-23 15:23:52
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Manipulation of Charge Transport by Metallic V <sub/>13</sub> O <sub/>16</sub> Decorated on Bismuth Vanadate Photoelectrochemical Catalyst
摘要: Conductive metal oxides represent a new category of functional material with vital importance for many modern applications. The present work introduces a new conductive metal oxide V13O16, which is synthesized via a simplified photoelectrochemical procedure and decorated onto the semiconducting photocatalyst BiVO4 in controlled mass percentages ranging from 25% to 37%. Owing to its excellent conductivity and good compatibility with oxide materials, the metallic V13O16-decorated BiVO4 hybrid catalyst shows a high photocurrent density of 2.2 ± 0.2 mA cm?2 at 1.23 V versus reversible hydrogen electrode (RHE). Both experimental characterization and density functional theory calculations indicate that the superior photocurrent derives from enhanced charge separation and transfer, resulting from ohmic contact at the interface of mixed phases and superior electrical conductivity from V13O16. A Co–Pi coating on BiVO4–V13O16 further increases the photocurrent to 5.0 ± 0.5 mA cm?2 at 1.23 V versus RHE, which is among the highest reported for BiVO4-based photoelectrodes. Surface photovoltage and transient photocurrent measurements suggest a charge-transfer model in which photocurrents are enhanced by improved surface passivation, although the barrier at the Co–Pi/electrolyte interface limits the charge transfer.
关键词: charge transport,bismuth vanadate,Co–Pi passivation,water oxidation,metallic V13O16
更新于2025-09-23 15:23:52
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Improved stability of silver nanowire (AgNW) electrode for high temperature applications using selective photoresist passivation
摘要: Metal nanostructure arrays have been progressed as an alternative to the conventional oxides-based transparent conductive electrodes. Herein, we demonstrate the improved reliability of silver nanowire (AgNW) electrodes by photoresist encapsulation. The incorporation of photoresist followed by photolithography is beneficial to selectively pattern the AgNWs on poly[ether sulfone]. By varying the development or removal time of the ultraviolet (UV)-exposed photoresist, the properties of the AgNWs in the electrode are significantly varied. The optical parameters such as transmittance, haziness, and the yellow index of the electrodes have been extensively studied to reveal the advantage of the selective photoresist patterning. The AgNW electrodes patterned under 120 s of development time explored superior optical and electrical properties with high durability. The electrical properties of the AgNW electrodes at high temperatures (250 °C) demonstrate the photoresist-induced stability as compared to bare samples. Further, the morphological examination after the high temperature treatment reveals the reduced Rayleigh instability effects in 120s developed AgNWs that facilitate the reliability under harsh conditions.
关键词: photoresist selective passivation,development time,high reliability,Silver nanowire (AgNW) electrode
更新于2025-09-23 15:23:52
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Influence of GaN- and Si?N?-Passivation Layers on the Performance of AlGaN/GaN Diodes With a Gated Edge Termination
摘要: This paper analyses the influence of the GaN and Si3N4 passivation (or 'cap') layer on the top of the AlGaN barrier layer on the performance and reliability of Schottky barrier diodes with a gated edge termination (GET-SBDs). Both GaN cap and Si3N4 cap devices show similar dc characteristics but a higher density of traps at the SiO2/GaN interface or/and an increase of the total dielectric constant in the access region result in higher RON-dispersion in GaN cap devices. The leakage current at medium/low temperatures in both types of devices shows two low-voltage-independent activation energies, suggesting thermionic and field-emission processes to be responsible for the conduction. Furthermore, a voltage-dependent activation energy in the high-temperature range occurs from low voltages in the GaN cap devices and limits their breakdown voltage (VBD). Time-dependent dielectric breakdown measurements show a tighter distribution in Si3N4 cap devices (Weibull slope β = 3.3) compared to GaN cap devices (β = 1.8). Additional measurements in plasma-enhanced atomic layer deposition (PEALD)-Si3N4 capacitors with different cap layers and TCAD simulations show an electric field distribution with a strong peak within the PEALD-Si3N4 dielectric at the GET corner, which could accelerate the formation of a percolation path and provoke the device breakdown in GaN cap SBDs even at low-stress voltages.
关键词: Si3N4 cap,GaN cap,AlGaN/GaN Schottky diode,reliability,breakdown voltage,passivation layer,off-state,Activation energy
更新于2025-09-23 15:23:52
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Surface passivation of GaAs (0?0?1) by Hg2Cl2 nanoplates combined with hexadecanethiol
摘要: Surface states in III–V semiconductor materials have detrimental effects on their optical and electronic properties, and the passivation of GaAs surface has become of longstanding interest. Here, we demonstrated a two-step process to greatly reduce surface states of GaAs (0 0 1) by a combination of Hg2Cl2 and alkanethiol. Firstly, uniformly distributed Hg2Cl2 nanoplates with a size around 200 nm were deposited on GaAs surface by the incubation of the etched wafer into the mercury (II) chloride solution, without the need of a reducing agent. Secondly, hexadecanethiol (HDT) molecules were assembled on the Hg2Cl2-GaAs hybrid surface, which decreases the density of surface states through electron transfer processes. Noticeably, after such two steps, a significant enhancement of photoluminescence (PL) signal was noted. It may be due to the fact that components of As2O3 and As0 which are identified as major sources of the surface states are reduced considerably, or even disappear. Chemical state changes of mercury species are expected to play a key role in achieving the surface passivation. Obtained hybrid GaAs materials with considerably improved photonic signals open a new avenue for the fabrication of electronic and optoelectronic devices.
关键词: Surface states,GaAs (0 0 1),Hg2Cl2 nanoplate,PL enhancement,Electrical passivation
更新于2025-09-23 15:22:29
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Improvement of Electrical Performance in P-Channel LTPS Thin-Film Transistor with a-Si:H Surface Passivation
摘要: We report the effects of surface passivation by depositing a hydrogenated amorphous silicon (a-Si:H) layer on the electrical characteristics of low temperature polycrystalline silicon thin film transistors (LTPS TFTs). The intrinsic a-Si:H layer was optimized by hydrogen dilution and its structural and electrical characteristics were investigated. The a-Si:H layer in the transition region between a-Si:H and μc-Si:H resulted in superior device characteristics. Using a-Si:H passivation layer, the field-effect mobility of the LTPS TFT was increased by 78.4% compared with conventional LTPS TFT. Moreover, the leakage current measured at VGS of 5 V was suppressed because the defect sites at the poly-Si grain boundaries were well passivated. Our passivation layer, which allows thorough control of the crystallinity and passivation-quality, should be considered as a candidate for high performance LTPS TFTs.
关键词: LTPS TFT,leakage current,poly-Si TFT,Raman,surface passivation,FT-IR
更新于2025-09-23 15:22:29
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Tuning Carbon Dots’ Optoelectronic Properties with Polymers
摘要: Due to their unique properties of photoluminescence, biocompatibility, photostability, ease of preparing, and low cost, carbon dots have been studied extensively over the last decade. Soon after their discovery, it was realized that their main optical attributes may be protected, enhanced, and tuned upon proper surface passivation or functionalization. Therefore, up to date, numerous polymers have been used for these purposes, resulting to higher-quality carbon dots regarding their quantum yield or further emission-related aspects and compared to the primitive, bare ones. Hence, this review aims to clarify the polymers’ role and effect on carbon dots and their features focusing on the quality characteristics of their photoluminescence upon passivation or functionalization. Given in fact the numbers of relevant publications, emphasis is given on recent articles capturing the latest advances for polymers in carbon dots for expanding emission lifetimes, advancing quantum yields, tuning emission wavelengths, enhancing specific spectral range absorption, and tailoring optoelectronic properties in general.
关键词: photoluminescence,functionalization,carbon dots,polymers,optoelectronic properties,surface passivation
更新于2025-09-23 15:22:29
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Sputter-Deposited-MoS2 nMISFETs with Top-Gate and Al2O3 Passivation under Low Thermal Budget for Large Area Integration
摘要: We have fabricated large area integrated top-gate nMISFETs with sputter-deposited-MoS2 film having n-type operation. A sputtering method enables us to form a large-area MoS2 thin film followed by H2S annealing to compensate sulfur vacancies. Two passivation films of ALD-Al2O3 enhance the process endurance of MoS2 channel. Therefore, we demonstrate TiN-top-gate nMISFET, which is a substantial first step to realize industrial chip-level LSIs with MoS2-channel FETs.
关键词: Top gate,MISFET,Transition metal di-chalcogenide,Sputtering,Passivation,Molybdenum disulfide,Large area integration
更新于2025-09-23 15:21:21
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<i>(Invited)</i> Proximity Gettering Design of Hydrocarbon Molecular Ion Implanted Silicon Wafers Using Direct Bonding Technique for Advanced CMOS Image Sensors: A Review
摘要: We developed high gettering capability silicon wafers for advanced CMOS image sensors using hydrocarbon molecular ion implantation and surface activated direct wafer bonding (SAB). We found that this novel wafer has three unique characteristics for the improvement of CMOS image sensor device performance. The first is metallic impurity gettering capability in the hydrocarbon ion implantation projection range during CMOS device fabrication. The second is the oxygen out-diffusion barrier effect; this wafer can control out-diffusion to the device active region from the CZ grown silicon substrate during CMOS device heat treatment. The third is the hydrogen passivation effect; hydrogen passivates to the Si/SiO2 gate oxide interface state defects which out-diffuse to the device active region from the hydrocarbon ion implantation projection range during the CMOS device fabrication. Moreover, we demonstrated that this novel wafer can improve the pn-junction leakage current under the actual device fabrication.
关键词: CMOS image sensors,hydrocarbon molecular ion implantation,surface activated direct wafer bonding,gettering capability,oxygen out-diffusion barrier,hydrogen passivation
更新于2025-09-23 15:21:21