共查询到19条相似文献,搜索用时 93 毫秒
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Si掺杂对AlGaInP/GaInP多量子阱性能的影响 总被引:1,自引:1,他引:0
采用LP-MOCVD技术在n-GaAs衬底上生长了AlGaInP/GaInP多量子阱红光LED外延片。以X射线双晶衍射技术和光致发光技术对外延片进行了表征,研究了Si掺杂对AlGaInP/GaInP多量子阱性能的影响。研究表明:掺Si能大大提高(Al0.3Ga0.7)0.5In0.5P/Ga0.5In0.5P多量子阱的发光强度。相对于未故意掺杂的样品,多量子阱垒层掺Si使多量子阱的发光强度提高了13倍,阱层和垒层均掺Si使多量子阱的发光强度提高了28倍。外延片的X射线双晶衍射测试表明,Si掺杂并没有使多量子阱的界面质量变差。 相似文献
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采用分子束外延技术(MBE)在Si(111)衬底上生长了非掺杂和Si掺杂砷化镓(GaAs)纳米线(NWs)。通过扫描电子显微镜(SEM)证实了生长样品的一维性;通过X射线衍射(XRD)测试和拉曼光谱(Raman)证实了掺杂GaAs纳米线中Si的存在;通过光致发光(PL)研究了非掺杂和Si掺杂GaAs纳米线的发光来源,掺杂改变了GaAs纳米线的辐射复合机制。掺杂导致非掺杂纳米线中自由激子发光峰和纤锌矿/闪锌矿(WZ/ZB)混相结构引起的缺陷发光峰消失。 相似文献
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对分子束外延生长带边激子发光的Si1-xGex/Si量子阱结构,通过Si离子自注入和不同温度退火,观测到深能级发光带和带边激子发光的转变.Si离子注入量子阱中并在600℃的低温退火,形成链状或小板式的团簇缺陷,它导致深能级发光带的形成,在850℃的高温退火后重新观测到带边激子发光.这种团簇缺陷的热离化能约为0.1eV,比Si中空穴或填隙原子缺陷的热激活能(约0.05eV)高.这表明早期文献中报道的深能级发光带是由类似的团簇缺陷产生的.
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利用金属有机化学气相沉积(MOCVD)方法在具有偏角(0°~0.9°)的Si(111)衬底上生长了GaN薄膜。采用高分辨X射线衍射(HRXRD)对Si衬底的偏角进行了精确的测量,利用HRXRD、原子力显微镜(AFM)以及光致发光(PL)对外延薄膜的晶体质量、量子阱中In组分、表面形貌及光学特性进行了研究。结果表明,Si(111)衬底偏角对量子阱中的In组分、 GaN外延膜的表面形貌、晶体质量以及光学性能具有重大影响。为了获得高质量的GaN外延薄膜,衬底偏角必须控制在小于0.5°的范围内。超出该范围,GaN薄膜的晶体质量、表面形貌及光学性能都明显下降。 相似文献
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Si衬底上ZnSe外延膜的低压MOCVD生长 总被引:2,自引:2,他引:0
以硒化氢(H2Se)和二甲基锌为源材料,生长温度是300℃时,用低压金属有机化学气相沉积(LP-MOCVD)系统在Si(111)衬底上外延生长了ZnSe薄膜。通过X射线衍射(XRD)、扫描电子显微镜的能量色散(EDS)以及光致发光(PL)实验验证ZnSe外延膜的质量,在X射线衍射谱中只有一个强的ZnSe(111)面衍射峰,这说明外延膜是(111)取向的单晶薄膜,在能量色散谱中除了Si,Zn和Se原子外,没有观测到其他原子,说明ZnSe外延膜中杂质含量较少。ZnSe外延膜中Zn/Se原子比接近1,有较好的化学配比。在ZnSe外延膜的77K光致发光谱中没有观测到与深中心发射相关的发光峰,表明ZnSe外延膜的晶格缺陷密度较小。77K时的近带边发射峰447nm在室温时移至465nm附近。 相似文献
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The photoluminescence (PL) of undoped, Si-doped, and Be-doped GaAs nanowires (NWs) grown on Si substrates by molecular beam epitaxy was investigated. PL peaks of the undoped and Be-doped NWs were observed at higher energies than the bandgap energy of GaAs bulk. According to X-ray diffraction analysis, the blue-shift is attributed to the wurtzite-rich GaAs NW structure. Impurity-related peaks were observed in the undoped NWs and the impurity was Si that diffused via interaction with the adatoms on the Si surface during the growth. A slight bandgap narrowing of the Be-doped GaAs NWs was observed from their PL spectra. The Si-doped NWs showed a very broad PL peak due to a larger density of Si-related defects originating from the heavy doping level. The dependence of the PL peaks of the NWs on temperature was also investigated. 相似文献
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D. J. Lockwood 《Phase Transitions》2013,86(1):151-168
Amorphous Si/SiO2 superlattices with periodicities between 2 and 5 nm have now been grown on (1 00) Si wafers by several different techniques: molecular beam epitaxy, magnetron sputtering, and plasma enhanced chemical vapor deposition (PECVD). With the first two methods little or no hydrogen is incorporated during growth and visible photo-luminescence (PL) is obtained at wavelengths from 520 to 800 nm. The shift in the PL peak position with Si layer thickness is consistent with quantum confined band-to-band recombination. Annealing the sputtered superlattices at temperatures up to 1100°C results in a very bright red PL that is similar in intensity to that observed in porous Si samples. For large numbers of periods (e.g., 425) the PL is strongly modulated in intensity owing to optical interference within the superlattice. Similar quantum confined, but defect induced, PL is also observed in the PECVD grown superlattices, where the amorphous Si layers are heavily hydrogenated. 相似文献
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用一种低成本的方法制备出了树形结构Si/ZnO纳米线阵列。首先在室温条件下用金属辅助化学腐蚀法在Si(100)衬底上制备了Si纳米线阵列,Si纳米线的直径尺寸及分布都很均匀,通过改变腐蚀时间,能够得到高度不同的Si纳米线阵列。利用磁控溅射在Si纳米线表面制备一层ZnO薄膜,然后利用水热法在Si纳米线阵列上生长了ZnO纳米线。通过扫描电子显微镜(SEM)、能谱分析仪(EDS)和光致发光(PL)测试对样品进行了表征。通过这种方法制备的Si/ZnO复合结构在太阳能电池、光催化等领域有潜在应用价值。 相似文献
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Yong RenYong-Bin Chen Miao ZhangJiang Zhu Xing-Wang ZhangYou-Yuan Zhao Ming Lu 《Applied Surface Science》2011,257(22):9578-9582
A multilayered Si nanocrystal-doped SiO2/Si (or Si-nc:SiO2/Si) sample structure is studied to acquire strong photoluminescence (PL) emission of Si via modulating excess Si concentration. The Si-nc:SiO2 results from SiO thin film after thermal annealing. The total thickness of SiO layer remains 150 nm, and is partitioned equally into a number of sublayers (N = 3, 5, 10, or 30) by Si interlayers. For each N-layered sample, a maximal PL intensity of Si can be obtained via optimizing the thickness of Si interlayer (or dSi). This maximal PL intensity varies with N, but the ratio of Si to O is nearly a constant. The brightest sample is found to be that of N = 10 and dSi = 1 nm, whose PL intensity is ∼5 times that of N = 1 without additional Si doping, and ∼2.5 times that of Si-nc:SiO2 prepared by co-evaporating of SiO and Si at the same optimized ratio of Si to O. Discussions are made based on PL, TEM, EDX and reflectance measurements. 相似文献
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Edward Sun 《Journal of luminescence》2010,130(8):1485-1488
The characteristics of temperature-dependent photoluminescence (PL) from Si nanocrystals and effects of arsenic-doping (As-doping) were investigated. The Si nanocrystals on a p-type Si substrate were prepared by low pressure chemical vapor deposition and post-deposition thermal oxidation. The As-doping process was carried out using the gas-phase-doping technique. Temperature-dependent PL from Si nanocrystals exhibited considerable differences between samples with/without As-doping. Phase transition between electron-hole liquid and free exciton was observed in the undoped Si nanocrystals, leading to the increase in PL intensity with temperature less than 50 K. Electron emission from As-doped Si nanocrystals to the p-Si substrate was responsible for the significant increase in PL intensity with temperature greater than 50 K. Characteristics of light emission from Si nanocrystals will facilitate the development of silicon-based nanoscaled light-emitting devices. 相似文献
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Template-based nanoscale epitaxy has been explored to realize high-quality GaN on Si(1 1 1) substrates. We have employed polystyrene-based nanosphere lithography to form the nano-hole array patterns on GaN/Si(1 1 1) template and then, subsequent regrowth of GaN is carried out by metalorganic chemical vapor deposition (MOCVD). During the initial growth stage of GaN on such nanopatterned substrates, we have observed formation of nanoislands with hexagonal pyramid shape due to selective area epitaxy. With further epitaxial regrowth, these nanoislands coalesce and form continuous GaN film. The overgrown GaN on patterned and non-patterned regions is characterized by high-resolution X-ray diffraction (HRXRD) and high-spatial resolution optical spectroscopic methods. Micro-photoluminescence (PL), micro-Raman scattering and scanning electron microscopy (SEM) have been used to assess the microstructural and optical properties of GaN. Combined PL and Raman data analyses show improved optical quality when compared to GaN simultaneously grown on non-patterned bulk Si(1 1 1). Such thicker GaN templates would be useful to achieve III-nitride-based opto- and electronic devices integrated on Si substrates. 相似文献
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Thin films consisting of the layers of phosphorus (P) and boron (B) co-doped Si nanocrystals (Si-ncs) and glass spacer layers were prepared and their photoluminescence properties were studied. Cross-sectional TEM observations revealed the growth of Si-ncs with narrow size distributions. The samples exhibited PL below the band gap energy of bulk Si crystal at room temperature. The low-energy PL is considered to arise from the transitions between donor and acceptor states in compensated Si-ncs. The successful formation of narrow size distribution co-doped Si nanocrystals promotes the study of the optical properties of compensated Si nanocrystals. 相似文献