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High mobility ultrathin ZnO p–n homojunction modulated by Zn_(0.85)Mg_(0.15)O quantum barriers 下载免费PDF全文
The adding of ZnMgO asymmetric double barriers(ADB) in p-ZnO:(Li, N)/n-ZnO homojunction affects the p–n junction device performance prominently. Two different homojunctions are fabricated on Si(100) substrates by pulsed laser deposition; one is the traditional p-ZnO:(Li, N)/n-ZnO homojunction with different thicknesses named as S_1 (250 nm) and S_2 (500 nm), the other is the one with ADB embedded in the n-layer named as Q (265 nm). From the photoluminescence spectra, defect luminescence present in the S-series devices is effectively limited in the Q device. The current–voltage curve of the Q device shows Zener-diode rectification property because the two-dimensional electron gas tunnels through the narrow ZnMgO barrier under a reverse bias, thus decreasing the working p–n homojunction thickness from 500 nm to265 nm. The ADB-modified homojunction shows higher carrier mobility in the Q device. The electroluminescence of the ZnO homojunction is improved in Q compared to S_2, because the holes in p-type ZnO(Li, N) can cross the wide ZnMgO barrier under a forward bias voltage into the ZnO quantum well. Therefore, electron–hole recombination occurs in the narrow bandgap of n-type ZnO, creating an ultraviolet light-emitting diode using the ZnO homojunction. 相似文献
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借助高温扫描隧道显微镜和光电子能谱技术,深入研究了SrO/Si(100)表面向Sr/Si(100)再构表面的动态转化过程.Sr/Si(100)再构表面在硅基氧化物外延生长中起重要作用.在该动态转化过程中,样品在500 ℃的退火温度下,表面出现SrO晶化的现象;在550—590 ℃的退火温度下,SrO/Si(100)开始向Sr/Si(100)转化,界面和表面上的氧以气态的SiO溢出,使得表面出现大量凹槽状缺陷.并且在此动态转化过程中表面的电子态表现出金属特性,这是由于表层硅原子发生断键重排,从而在表面出现悬
关键词:
SrO/Si表面
Sr/Si表面
扫描隧道显微镜
去氧过程 相似文献
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本文工作利用脉冲激光沉积术(PLD)和超高真空扫描隧道显微术(UHV-STM),研究了在Sr/Si(001)-(2×1)衬底表面上真空室温沉积几个单层SrTiO3薄膜的初始生长过程.经660 ℃退火处理后,Sr/Si衬底表面上形成了纳米岛状结构.经分析,这些纳米小岛为C49-TiSi2和 C54-TiSi2.实验结果表明,在没有氧气的情况下退火,Sr/Si界面无法有效阻止SrTiO3薄膜与Si衬底之间的相互作用.
关键词:
脉冲激光沉积术(PLD)
扫描隧道显微镜(STM)
3')" href="#">SrTiO3
2')" href="#">C54-TiSi2 相似文献
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为了解半导体衬底与氧化物之间存在的相互作用,以及量子尺寸效应对不同再构体的影响,制备了1—2个原子层厚的TiSi2/Si(100)纳米岛,并使用扫描隧道显微镜(STM)表征手段详细地研究了TiSi2 /Si(100)纳米岛的电子和几何特性. 结果发现:这些纳米岛表面显示出明显的金属性;其空态STM图像具有典型的偏压依赖性:在高偏压下STM 图像由三聚物形成的单胞构成,并在低偏压下STM 图像显示为密堆积的图案,这些不同的图案反映出不同能量位的态密度有明显差异.
关键词:
2纳米岛')" href="#">TiSi2纳米岛
Sr/Si(100)表面
扫描隧道显微镜 相似文献
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An Sr/Si(100)-c(2×4) surface is investigated by high-resolution scanning tunneling microscopy(STM) and scanning tunneling spectroscopy(STS).The semiconductor property of this surface is confirmed by STS.The STM images of this surface shows that it is bias-voltage dependent and an atomic resolution image can be obtained at an empty state under a bias voltage of 1.5 V.Furthermore,one-dimensional(1D) diffusion of vacancies can be found in the room-temperature STM images.Sr vacancies diffuse along the valley channels,which are constructed by silicon dimers in the surface.Weak interaction between Sr and silicon dimers,low metal coverage,surface vacancy,and energy of thermal fluctuation at room temperature all contribute to this 1D diffusion. 相似文献
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An Sr/Si(100)-c(2×4) surface is investigated by high-resolution scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS). The semiconductor property of this surface is confirmed by STS. The STM images of this surface shows that it is bias-voltage dependent and an atomic resolution image can be obtained at an empty state under a bias voltage of 1.5 V. Furthermore, one-dimensional (1D) diffusion of vacancies can be found in the room-temperature STM images. Sr vacancies diffuse along the valley channels, which are constructed by silicon dimers in the surface. Weak interaction between Sr and silicon dimers, low metal coverage, surface vacancy, and energy of thermal fluctuation at room temperature all contribute to this 1D diffusion. 相似文献
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