共查询到19条相似文献,搜索用时 62 毫秒
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利用MOCVD方法在(0001)取向的蓝宝石衬底上实现了不同工艺条件下的高质量AlGaN材料的制备.得到了无裂纹的全组分AlxGa1-xN(0<x<1)薄膜.通过XRD,SEM,AFM等测量分析方法系统研究了生长工艺参数对材料的结构质量、组分、厚度和表面形貌的影响.分析了不同生长工艺对AlGaN材料特性的影响.研制的高质量AlGaN材料在紫外探测器的DBR结构应用中得到比较好的特性. 相似文献
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研究了GaN肖特基结构(n--GaN /n+-GaN)紫外探测器的结构参数对器件性能的影响机理。模拟计算结果表明:提高肖特基势垒高度和减小表面复合速率,不仅可以增加器件的量子效率,而且可以极大地减小器件的暗电流;适当地增加n--GaN层厚度和载流子浓度可以提高器件的量子效率,但减小n--GaN层的载流子浓度却有利于减小器件的暗电流。我们针对实际应用的需要,提出了一个优化器件结构参数的设计方案,特别是如果实际应用中对器件的量子效率和暗电流都有较高的要求,肖特基势垒高度应该≥0.8 eV,n--GaN层的厚度≥200 nm,载流子浓度1×1017 cm-3 左右,表面复合速率<1×107 cm/s。 相似文献
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Au电极厚度对MgZnO紫外探测器性能的影响 总被引:1,自引:0,他引:1
利用分子束外延设备(MBE)制备了MgZnO薄膜.X射线衍射谱、紫外-可见透射光谱和X射线能谱表明薄膜具有单一六角相结构,吸收边为340 nm,Zn/Mg组分比为62:38.采用掩膜方法使用离子溅射设备,在MgZnO薄膜上制备了Au电极,并实现了Au-MgZnO-Au结构的紫外探测器.通过改变溅射时间,得到具有不同Au电极厚度的MgZnO紫外探测器.研究结果表明:随着Au电极厚度的增加,导电性先缓慢增加,再迅速增加,最后缓慢增加并趋于饱和;而Au电极的透光率则随厚度的增加呈线性下降.此外,随着Au电极厚度的增加,器件光响应度先逐渐增大,在Au电极厚度为28 nm时达到峰值,之后逐渐减小. 相似文献
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提出一种在AlGaN基PIN器件的p-GaN表面上沉积Pt,形成肖特基势垒(SB)-PIN异质结器件,器件的能带和载流子的输运发生了变化,这种新型光电探测器实现了双波段紫外探测,可分别工作在光伏和光电导模式下。器件在275 nm波长的紫外光照射的负偏置电压下,工作模式为光伏探测,当入射光功率密度为100μW/cm2,偏置电压为-10 V时,器件得到最大响应度(0.12 A/W);当偏置电压为-0.5 V时,器件得到最大探测率(1.0×1013 cm·Hz1/2·W-1)。器件在正偏置电压工作模式下可作为高响应、高增益的光电导探测器,当偏置电压为+10 V时,用275 nm和365 nm波长的紫外光照射(光功率密度为100μW/cm2),器件的响应度分别为10 A/W和14 A/W,外量子效率分别为4500%和4890%。所设计的双波段多功能器件将极大地扩展基于AlGaN的紫外探测器的用途。 相似文献
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Significant Improvement of Passivation Performance by Two-Step Preparation of Amorphous Silicon Passivation Layers in Silicon Heterojunction Solar Cells 下载免费PDF全文
《中国物理快报》2017,(3)
The key feature of amorphous/crystalline silicon heterojunction solar cells is extremely low surface recombination,which is related to superior passivation on the crystalline silicon wafer surface using thin hydrogenated amorphous silicon(a-Si:H)layers,leading to a high open-circuit voltage.In this work,a two-step method of a-Si:H passivation is introduced,showing excellent interface passivation quality,and the highest effective minority carrier lifetime exceeds 4500 μs.By applying a buffer layer deposited through pure silane plasma,the risk of film epitaxial growth and plasma damage caused by hydrogen diluted silane plasma is effectively reduced.Based on this,excellent passivation is realized through the following hydrogen diluted silane plasma process with the application of high density hydrogen.In this process,hydrogen diffuses to a-Si/c-Si interface,saturating residual dangling bonds which are not passivated by the buffer layer.Employing this two-step method,a heterojunction solar cell with an area of 239 cm~2 is prepared,yielding to open-circuit voltage up to 735 mV and total-area efficiency up to 22.4%. 相似文献
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针对AlGaN基多量子阱中有效的平衡载流子注入问题,研究了有源区势垒层中Al组分调制形成的非规则H形量子势垒对AlGaN基深紫外发光二极管(LED)器件性能的影响及载流子的输运行为。研究发现,与多量子阱中常用的单Al组分势垒相比,加入Al组分较高的双尖峰势垒可以有效地提高内量子效率和光输出功率。进一步研究表明,电子在有源区因凸起的尖峰势垒而得到了有效的阻挡,减少了电子的泄露,而空穴获得更多的动能从而穿过较高的势垒进入有源区。因此,采用非对称H形量子势垒的深紫外LED器件中载流子输运实现了较好的平衡,量子阱中的载流子复合速率远高于普通的深紫外发光二极管。 相似文献
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为了有效降低GaAs半导体表面态密度,提出了采用正十八硫醇(ODT,CH3[CH2]17SH)进行GaAs表面钝化的方案。首先,分别对GaAs(100)晶片进行了常规硫代乙酰胺(TAM,CH3CSNH2)钝化和正十八硫醇钝化,通过X射线光电子能谱(XPS)对比分析了钝化前后晶片表面的化学成分,然后利用光致发光光谱(PL)对正十八硫醇处理的GaAs(100)晶片进行了钝化时间的优化,最后通过扫描电子显微镜(SEM)测试了钝化前后的晶片表面形貌。实验结果表明:采用正十八硫醇钝化的GaAs(100)表面,相比常规硫代乙酰胺钝化方案,具有更低的氧化物含量和更厚的硫化层厚度;室温钝化条件下,钝化时间越长,正十八硫醇的钝化效果越好,但PL强度在钝化超过24 h后基本达到稳定,最高PL强度提高了116%;正十八硫醇钝化的GaAs(100)晶片具有良好的表面形貌,表面形成了均匀、平整的硫化物钝化层。数据表明正十八硫醇是钝化GaAs(100)表面一种非常有效的技术手段。 相似文献
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Black silicon (BS) layers coated with passivation films are widely used as antireflective frontal surfaces for solar cells. The most common BS fabrication techniques are reactive ion etching (RIE), metal-assisted chemical etching, and laser-induced processing. Herein, the structural and optical properties, as well as the minority carrier lifetime, of BS are compared with and without atomic layer deposited HfO2 passivation films produced by the above formation methods. The antireflection behavior of the samples is discussed based on the light trapping effect and the change in the BS refractive index from air to the bulk of crystalline Si. Finally, test solar cells are manufactured, and their photovoltaic parameters are studied. The comparison results show that RIE is the most preferred in all technical respects. The features of using different BS fabrication techniques from the solar cell manufacturing point of view are analyzed. 相似文献
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A.G.U. Perera G. Ariyawansa M.B.M. Rinzan M. Stevens M. Alevli N. Dietz S.G. Matsik A. Asghar I.T. Ferguson H. Luo A. Bezinger H.C. Liu 《Infrared Physics & Technology》2007,50(2-3):142-148
Results are reported on dual-band detectors based on a GaN/AlGaN structure operating in both the ultraviolet–midinfrared (UV–MIR) and ultraviolet–farinfrared (UV–FIR) regions. The UV detection is due to an interband process, while the MIR/FIR detection is from free carrier absorption in the emitter/contact followed by internal photoemission over the barrier at the GaN/AlGaN interface. The UV detection, which was observed from 300 K to 4.2 K, has a threshold of 360 nm with a peak responsivity of 0.6 mA/W at 300 K. The detector shows a free carrier IR response in the 3–7 μm range up to 120 K, and an impurity response around 54 μm up to 30 K. A response in the range 7–13 μm, which is tentatively assigned to transitions from C impurities and N vacancies in the barrier region, was also observed. It should also be possible to develop a detector operating in the UV–visible–IR regions by choosing the appropriate material system. A dual-band detector design, which allows not only to measure the two components of the photocurrent generated by UV and IR radiation simultaneously but also to optimize the UV and IR responses independently, is proposed. 相似文献