共查询到20条相似文献，搜索用时 62 毫秒
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在4H-SiC外延材料上制备了SBD和JBS器件,研究并分析了退火温度对这两种器件正反向特性的影响。结果表明,低于350℃退火可同时提高SBD和JBS的正反向特性。当退火温度高于350℃时,二者的正向特性都出现退化,SBD退化较JBS更为严重。JBS阻断电压随退火温度升高而增大,在退火温度高于450℃时增加趋势变缓。SBD阻断电压随退火温度升高先升后降,在500℃退火时达到一个最大值。可见一定程度的退火有助于提高4H-SiCSBD和JBS器件的正反向特性,但须考虑其对正反向特性的不同影响。综合而言,退火优化后JBS优于SBD器件性能。 相似文献
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4H-SiC SBD和JBS退火研究 总被引：1，自引：0，他引：1
在4H-SiC外延材料上制备了SBD和JBS器件,研究并分析了退火温度对这两种器件正反向特性的影响。结果表明,低于350℃退火可同时提高SBD和JBS的正反向特性。当退火温度高于350℃时,二者的正向特性都出现退化,SBD退化较JBS更为严重。JBS阻断电压随退火温度升高而增大,在退火温度高于450℃时增加趋势变缓。SBD阻断电压随退火温度升高先升后降,在500℃退火时达到一个最大值。可见一定程度的退火有助于提高4H-SiCSBD和JBS器件的正反向特性,但须考虑其对正反向特性的不同影响。综合而言,退火优化后JBS优于SBD器件性能。 相似文献
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1 引言 近半个世纪以来,红外物理和红外技术在军事需要的推动下发展非常迅速,已形成一个相对独立的学科,也造就了一个庞大的产业。根据20世纪90年代初的统计,美国仅从事红 相似文献
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孙正阳;季凌飞;林真源;张彤;许园波;张犁天 《中国激光》2020,(8):52-60
采用KrF准分子激光辐照4H-SiC制备石墨烯层,从4H-SiC晶面取向对石墨烯生长质量影响的角度开展研究工作,分析激光能量密度、脉冲数及晶面取向对石墨烯质量的影响。当激光能量密度为1.06 J/cm2,脉冲数为8000时,4H-SiC样品极性Si（0001）面和非极性■面上生长的石墨烯质量均达到最好。石墨烯与4H-SiC衬底极性Si（0001）面之间存在缓冲层,为石墨烯的生长提供了模板,得到的石墨烯更为有序,缺陷态更少;而非极性■面上生成的石墨烯与衬底之间未生成缓冲层,生长的石墨烯层较为无序,对激光参数的变化更为敏感。 相似文献
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激光辐照对PZT-4陶瓷介电性能的影响 总被引：1，自引：0，他引：1
研究了CO2激光辐照对PZT-4陶瓷介电性能的影响。在一定的激光辐照功率密度下,PZT-4陶瓷的介电常数下降约5%,介电损耗下降约60%,矫顽场增加。结合拉曼光谱、扫描电子显微镜、X射线衍射以及后退火处理探讨了激光辐照PZT-4陶瓷的改性机理,结果表明,激光辐照后陶瓷介电性能的变化主要与其微结构有关,辐照使得陶瓷产生了较大的张应力,晶格常数变大,B位离子更容易偏离氧八面体中心,氧八面体扭曲,使其电畴活性下降,阻碍了极化翻转,材料性能变"硬"。 相似文献
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Bo Cai Yangzhi Ma Bing Yang Yi Liu Junmin Xia Xi Chen Zhi Li Ming-Gang Ju 《Advanced functional materials》2023,33(29):2300445
Halide perovskites have attracted much attention because of their excellent optoelectronic properties, such as high light absorption, long carrier diffusion length, and high defect tolerance. Ion migration induced device performance degradation, which is not yet fully understood, has become the key obstacle for commercialization of halide perovskites. Here, a general mechanism is proposed, which can build up the connection between the ion migration barrier and the electronic density of states, to clarify the origin of low barrier for ion migration. Density functional theory (DFT) simulation results show that the low barrier is caused by a significant energy difference in band centers between Pb2+ and the isolating halogen anion or by the small number of density of states. Following the explored mechanism, two strategies are proposed to boost barriers via DFT combination CI-NEB simulations: 1) halide double perovskites and 2) B-site doping. Furthermore, the finding not only deepens the understanding of ion migration in halide perovskites but also paves a new path for the commercialization of halide perovskite optoelectronic devices. 相似文献
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Alex L. Krick Chan‐Woo Lee Rebecca J. Sichel‐Tissot Andrew M. Rappe Steven J. May 《Advanced Electronic Materials》2016,2(6)
The electronic properties of digital superlattices are reported, which are cation‐ordered analogs of the perovskite La1/3Sr2/3FeO3, a material that undergoes a charge‐ordering transition. Superlattices of LaFeO3 (LFO), an antiferromagnetic insulator, and SrFeO3 (SFO), a conductor with a helical magnetic ground state, are fabricated via oxide molecular beam epitaxy. Three isocompositional superlattices with repeat structures of SSLSSL (S2), SSSLSL (S3), and SSSSLL (S4) (S = SFO, L = LFO) are studied with cation orderings along the [001] and [111] directions for experimental and computational work, respectively. The experimental superlattice structures are confirmed via synchrotron X‐ray diffraction and corresponding simulations of (00L) crystal truncation rods. The S2 and S3 superlattices are found to undergo an electronic phase transition as measured by a discontinuity in the temperature‐dependent resistivity similar to the random alloy, indicating that the superlattices do not behave as a simple combination of LFO and SFO. The charge‐ordering transition is not observed in the S4 sample. The electronic structure calculations using density functional theory, confirming the energetic favorability of charge ordering in the S2 and S3 structures compared to the S4 structure, are consistent with experimental trends. 相似文献
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Yan Pei Wenhao Geng Lingbo Xu Can Cui Xiaodong Pi Deren Yang Rong Wang 《半导体学报》2024,45(11):112503-1-112503-7
4H silicon carbide (4H-SiC) has gained a great success in high-power electronics, owing to its advantages of wide bandgap, high breakdown electric field strength, high carrier mobility, and high thermal conductivity. Considering the high carrier mobility and high stability of 4H-SiC, 4H-SiC has great potential in the field of photoelectrochemical (PEC) water splitting. In this work, we demonstrate the irradiation-resistant PEC water splitting based on nanoporous 4H-SiC arrays. A new two-step anodizing approach is adopted to prepare 4H-SiC nanoporous arrays with different porosity, that is, a constant low-voltage etching followed by a pulsed high-voltage etching. The constant-voltage etching and pulsed-voltage etching are adopted to control the diameter of the nanopores and the depth of the nanoporous arrays, respectively. It is found that the nanoporous arrays with medium porosity has the highest PEC current, because of the enhanced light absorption and the optimized transportation of charge carriers along the walls of the nanoporous arrays. The performance of the PEC water splitting of the nanoporous arrays is stable after the electron irradiation with the dose of 800 and 1600 kGy, which indicates that 4H-SiC nanoporous arrays has great potential in the PEC water splitting under harsh environments. 相似文献
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Xinqing Han Runhan Li Shangfa Pan Yong Liu Chengwang Niu Miguel L. Crespillo Eva Zarkadoula Peng Liu 《Advanced functional materials》2024,34(42):2405885
The relationship between the composition of the internal defect states, spectral properties, and correlated electronic structures of wurtzite zinc oxide (ZnO) crystals under 645 MeV Xe35+ irradiation is systematically investigated, employing experimental characterizations combined with first-principle calculations. Based on the ion irradiation-induced thermal expansion and relaxation processes, the high concentration of vacancy/interstitial defects produced from the transient disordered phase in molten track states trigger photoelectric changes, as follows: i) the generation of internal defect states effectively reduces the intrinsic bandgap (3.25 eV → 2.66 eV); ii) a large number of defective active sites inhibits the recombination between electron–hole pairs, causing dark conductance and photoconductance to increase with increasing damage levels until optimal fluence is achieved. Based on the density functional theory (DFT) with the GGA + U (GGA = generalized gradient approximation) method, the defective models associated with the different electronic structures, density of states, formation energy, and the nature of the chemical bonding are established. The narrowing of the bandgap observed experimentally and the enhancement of carrier concentration originating from the internal electron defect states are qualitatively verified, therefore laying the foundation for designing future nanoscale photoelectronic devices and microelectronics applications. 相似文献
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采用二维器件模拟器ISE TCAD 7.0,对比研究了6H-SiC和4H-SiC VDMOS的基本特性.结果表明,在Vgs为8 V时,4H-SiC VDMOS的漏极电流比6H-SiC高约1.5倍,证实了4H-SiC具有较高的体迁移率,且受准饱和效应的影响较小,因此比6H-SiC器件具有更高的饱和电流密度,而两种器件的阈值电压基本相同,均为7 V左右.对器件开关时间和单位面积损耗的分析表明,4H-SiC比6H-SiC更适合用于VDMOS功率器件.此外,还研究了沟道长度对器件漏极饱和电流的影响,结果表明,随着沟道长度的减小,器件的漏极电流增大. 相似文献
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Shenglin Zhu Zijian Li Liqiang Hou Min Gyu Kim Haeseong Jang Shangguo Liu Xien Liu 《Advanced functional materials》2024,34(17):2314899
Modulating the electronic asymmetricity of catalysts is an effective method for optimizating the elementary steps of water dissociation and hydrogen adsorption/desorption process for the alkaline hydrogen evolution reaction (HER). Herein, uniform Ru nanoclusters anchored on N doped ultrathin carbon nanosheets (Ru/NC) are synthesized to optimize the asymmetricity electronic properties of supported Ru for efficient HER. It is found that Ru and NC with a large work function difference (ΔΦ) leading to the formation of stronger asymmetrical charge distributions of Ru that electron-deficient high-valence Ru (Run+) coupling with low-valence Ru (Ru0). Experimental and theoretical studies indicate the Run+ sites lowered the energy barrier for water dissociation and provided enough hydrogen proton to promote the hydrogen spillover from the Run+ to Ru0 sites, and Ru0 sites can enhance H desorption process, thus synergistically enhancing the hydrogen evolution activity. Notably, the Ru/NC catalyst exhibits a high alkaline HER activity (21.9 mV@10 mA cm−2, 29.03 mV dec−1). The role of electronic asymmetricity on supported Ru nanoclusters for the alkaline HER are demonstrated, which will provide guidelines for the rational design of high-efficiency alkaline HER catalysts. 相似文献
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4H-SiC MESFET的反应离子刻蚀和牺牲氧化工艺研究 总被引：2，自引：0，他引：2
对于栅挖槽的4H-SiCMESFET,栅肖特基接触的界面经过反应离子刻蚀,界面特性对于肖特基特性和器件性能至关重要。反应离子刻蚀的SiC表面平滑度不是很好,刻蚀损伤严重。选择合适的RIE刻蚀条件减小刻蚀对半导体表面的损伤;利用牺牲氧化改善刻蚀后的表面形貌,进一步减小表面的刻蚀损伤。工艺优化后栅的肖特基特性有了明显改善,理想因子接近于1。制成的4H-SiCMESFET直流夹断特性良好,饱和电流密度达到350mAmm。 相似文献