共查询到18条相似文献,搜索用时 156 毫秒
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黄永南 《固体电子学研究与进展》1982,(4)
本文简要介绍了液氦表面、半导体表面空间电荷层和化合物半导体异质结界面的二维电子气.积累在选择掺杂GaAs/Al_xGa_(1-x)A_s异质结界面的二维电子气在低温下迁移率剧增.调制掺杂GaAs/Al_xGa_(1-x)A_s超晶格是一个适合于研究量子态和次带能级的系统.因而,异质结界面处二维电子气的研究,不仅可能为新的高速和微波器件的探索打开新的途径,而且还提供了研究量子效应的新领域. 相似文献
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本文对调制掺杂GaAs/Al_xGa_(1-x)As异质结材料进行无包封过砷压下高温退火。与未经退火材料相比较,高温退火会引起调制掺杂材料的电学性质明显退化.基于Hall和I-V特性测量结果,对造成二维电子气(2-DEG)迁移率下降的原因进行了分析和讨论. 相似文献
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蝶形天线增强的HEMT室温太赫兹探测器 总被引:1,自引:1,他引:0
介绍了一种基于GaN/AlGaN高电子迁移率晶体管(HEMT)的高速、高灵敏度室温太赫兹探测器。在太赫兹波辐射下,HEMT源漏端产生直流光电流,并能被栅压灵敏地调控。探测器中新颖的蝶形天线设计使接收到的太赫兹电场得到显著增强,提高了探测器的响应度。通过测量探测器对不同偏振方向的太赫兹光的响应,有效验证了蝶形天线对太赫兹电场的增强作用。室温下,探测器的等效噪声功率约为5×10-10W/Hz21,平均响应度达42mA/W。实验结果表明,光电流的产生与二维电子气沟道的场效应特性和入射太赫兹波电场在电子沟道中的分布密切相关。自混频理论能很好地描述实验结果。 相似文献
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用分子束外延生长Al_xGa_(1-x)As/GaAs调制掺杂结构。范德堡法、光荧光谱和电化学C—V等方法测量了电学和光学特性。连续波电光检测证明材料有较好的均匀性。用该结构材料制作的HEMT器件在12GHz下,噪声系数0.76dB,相关增益6.5dB。 相似文献
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从 3个层面研究了分子束外延 Al0 .48In0 .52 As/ Ga0 .47In0 .53As/ In P功率 HEMT结构材料生长技术。首先 ,通过观察生长过程的高能电子衍射 (RHEED)图谱 ,确立了 Ga0 .47In0 .53As/ In P结构表面层的 MBE RHEED衍射工艺相图 ,据此生长的单层 Si-doped Ga0 .47In0 .53As(40 0 nm) / In P室温迁移率可达 6960 cm2 / V· s及电子浓度 1 .3 3 E1 7cm- 3。其次 ,经过优化结构参数 ,低噪声 Al0 .48In0 .52 As/ Ga0 .47In0 .53As/ In P HEMT结构材料的 Hall参数达到μ30 0 K≥ 1 0 0 0 0 cm2 / V· s、2 DEG≥ 2 .5 E1 2 cm- 2 。最后 ,在此基础之上 ,降低 spacer的厚度、在 Ga0 .47In0 .53As沟道内插入 Si平面掺杂层并增加势垒层的掺杂浓度获得了功率 Al0 .48In0 .52 As/ Ga0 .47In0 .53As/ In PHEMT结构材料 ,其 Hall参数达到μ30 0 K≥ 80 0 0 cm2 / V· s、2 DEG≥ 4 .0 E1 2 cm- 2 。 相似文献
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The long wavelength optical phonon spectra of AlxGa1-xAs mixed crystals appear as "two-mode" behaviour, i.e. there are GaAs-like and AlAs-like optical branches simultaneously. Besides* the LO phonon dispersion curves of bulk GaAs and GaAs-like in AlxGa1-xAs mixed crystal are partly overlapped. Therefore, we expect, in GaAs/AlxGa1-xAs superlattices, that LO phonons are partly in confined modes while partly in folded one, and that AlAs-like modes are confined in AlxGa1-xAs layers.The samples of GaAs/AlxGa1-xAs superlattices were grown by MBE on (001) oriented semi-insulating GaAs substrates. Raman spectra were measured in the back-scattering geometry at room temperature. Only odd modes with B2 symmetry were observed for LO modes confined in the GaAs layer. This result is in agreement with the previous reports. In addition, AlAs-like LO modes confined in AlxGa1-xAs layers were observed for the first time. 相似文献
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Witkowski L.C. Drummond T.J. Barnett S.A. Marko? H. Cho A.Y. Greene J.E. 《Electronics letters》1981,17(3):126-128
Single period modulation-doped structures composed of an AlxGa1?xAs layer, part of which is doped with Si, on top of an undoped GaAs layer have been grown by molecular beam epitaxy. The films were characterised using Hall effect measurements carried out at temperatures between 10 and 300 K. With 50?75 ? thick undoped (Al, Ga)As layers near the interface, mobilities in excess of 115000 cm2/Vs at 10 K and 7450 cm2/Vs at 300 K have been achieved for an average doping concentration of ?5×1016 cm?3. These are some of the highest mobilities as yet obtained from modulation-doped structures, and represent an increase in mobility over equivalently doped GaAs by about a factor of 20 at 10 K and by a factor of 2 at 300 K. 相似文献
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A novel FET using a 2DEG is presented. The FET has an AlAs/GaAs/AlAs single quantum well with planar doping in the centre of the GaAs layer. The conduction channels are composed of a 2DEG generated in undoped GaAs layers outside the well. The measured 2DEG concentration was 1.8?2 × 1012cm?2 with electron mobilities of 3500cm2/Vs at RT and 10500cm2/Vs at 77K. A 1.5?m-gate-length FET exhibits a maximum transconductance of 174 mS/mm and a maximum current exceeding 300 mA/mm at 77K. 相似文献
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采用基于LMTO-ASA的平均键能计算方法和原子集团展开方法,研究了三组典型的晶格匹配三元合金异质结(GaAs)x(Ge2)1-x/GaAs,(AlAs)x(Ge2)1-x/GaAs和AlxGa1-xAs/GaAs的价带带阶△Ev(x)值。研究表明:AlxGa1-xAs/GaAs异质结的Mv(x)值随合金组分x的变化接近于线性;(GaAs)x(Ge2)1-x/GaAs和(AlAs)x(Ge2)1-x/GaAs的△Ev(x)值随合金组分x的变化是非线性的。△Ev(x)的理论计算值与实验结果相当符合。 相似文献
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设计了一种基于场效应晶体管的量子点场效应单光子探测器,利用二维弛豫时间的近似理论建立了二维电子气电子迁移率的散射模型,通过求解量子点场效应单光子探测器GaAs/AlxGa1-xAs二维电子气系统电子和声子相互作用的Hamiltonian函数,得到了不同温度、不同Al组分以及不同二维电子气电子面密度条件下晶格振动散射对探测器二维电子气电子迁移率的影响.仿真结果显示,提高二维电子气的电子面密度浓度和适当增大Al组分,并降低工作温度,有助于探测器获得更高的二维电子气电子迁移率. 相似文献
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应用透射式电子显微镜观察了GaAs-Al_xGa_(1-x)As多层异质结结构中的“精细低维调制条纹”。在邻近GaAs-Al_xGa_(1-x)As超晶格层的缓冲层中和与这缓冲层邻近的GaAs-Al_xGa_(1-x)As超晶格层的小区域中发现了等宽度的“精细低维调制条纹”,其宽度为9.1(?)的GaAs条纹,12(?)的Al_xGa_(1-x)As条纹。文中介绍了用显微密度计获得的这些条纹的密度分布结果。同时还给出了GaAs-Al_xGa_(1-x)As 多层异质结结构的晶格像和用X射线能量散射谱技术获得的成分定量分析结果。 相似文献