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1.
在变缓冲层高迁移率晶体管(MM_HEMT)器件中,二维电子气的输运性质对器件性能起着决定作用.通过低温下二维电子气横向电阻的量子振荡现象,结合变温度的Hall测量,系统研究了不同In组分沟道MM_HEMT器件中子带电子迁移率和浓度随温度的变化关系.结果表明,沟道中In组分为0.65的样品,材料电学性能最好,In组分高于0.65的样品,严重的晶格失配将产生位错,引起迁移率下降,大大影响材料和器件的性能.
关键词:
变缓冲层高迁移率晶体管
Shubnikov_de Hass 振荡 相似文献
2.
Influence of Ⅴ/Ⅲ ratio on the structural and photoluminescence properties of In0.52AlAs/In0.53GaAs metamorphic high electron mobility transistor grown by molecular beam epitaxy
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A series of metamorphic high electron mobility transistors (MMHEMTs) with different Ⅴ/Ⅲ flux ratios are grown on CaAs (001) substrates by molecular beam epitaxy (MBE). The samples are analysed by using atomic force microscopy (AFM), Hall measurement, and low temperature photoluminescence (PL). The optimum Ⅴ/Ⅲ ratio in a range from 15 to 60 for the growth of MMHEMTs is found to be around 40. At this ratio, the root mean square (RMS) roughness of the material is only 2.02 nm; a room-temperature mobility and a sheet electron density are obtained to be 10610.0cm^2/(V.s) and 3.26×10^12cm^-2 respectively. These results are equivalent to those obtained for the same structure grown on InP substrate. There are two peaks in the PL spectrum of the structure, corresponding to two sub-energy levels of the In0.53Ga0.47As quantum well. It is found that the photoluminescence intensities of the two peaks vary with the Ⅴ/Ⅲ ratio, for which the reasons are discussed. 相似文献
3.
Influence of spacer layer thickness on the current-voltage characteristics of pseudomorphic AlAs/In0.53Ga0.47As/InAs resonant tunnelling diodes
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This paper investigates the dependence of current voltage characteristics of AlAs/In0.53Ga0.47As/InAs resonant tunnelling diodes (RTDs) on spacer layer thickness. It finds that the peak and the valley current density J in the negative differential resistance (NDR) region depends strongly on the thickness of the spacer layer. The measured peak to valley current ratio of RTDs studied here is shown to improve while the current density through RTDs decreases with increasing spacer layer thickness below a critical value. 相似文献
4.
Organic Light Emitting Diodes with an Organic Acceptor/Donor Interface Involved in Hole Injection
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Organic light emitting diodes with an interface of organic acceptor 3-, 4-, 9-,10-perylenetetracarboxylic dianhydride (PTCDA) and donor copper phthalocyanine (CuPc) involved in hole injection are fabricated. As compared to the conventional device using a 5 nm CuPc hole injection layer, the device using an interface of 10nm PTCDA and 5 nm CuPc layers shows much lower operating voltage with an increase of about 46% in the maximum power efficiency. The enhanced device performance is attributed to the efficient hole generation at the PTCDA/CuPc interface. This study provides a new way of designing hole injection. 相似文献
5.
新型高效太阳能电池研究进展 总被引:1,自引:0,他引:1
第三代太阳能电池以超高效率、薄膜化、低成本为主要目标,目前发展起来的有多结叠层太阳能电池、中间带太阳能电池、多激子产生太阳能电池、热载流子太阳能电池和热光伏太阳能电池等.文章简要介绍了以上几种新型太阳能电池的工作原理和最新进展,并对其发展前景作了分析和预测. 相似文献
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7.
Synthesis and Characterization of ZnO Nanoflowers Grown on AlN Films by Solution Deposition
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ZnO nanoflowers are synthesized on AlN films by solution method. The synthesized nanoflowers are composed of nanorods, which are pyramidal and grow from a central point, thus forming structures that are flower-shaped as a whole. The nanoflowers have two typical morphologies: plate-like and bush-like. The XRD spectrum corresponds to the side planes of the ZnO nanorods made up of the nanoflowers. The micro-Raman spectrum of the ZnO nanoflowers exhibits the E2 (high) mode and the second order multiple-phonon mode. The photoluminescence spectrum of the ZnO nanoflowers exhibits ultraviolet emission centred at 375nm and a broad green emission centred at 526 nm. 相似文献
8.
AlSb/InAs quantum well (QW) structures and InAs films on GaAs (001) substrates were grown by molecular beam epitaxy (MBE). We investigated the dependence of electron mobility and two-dimensional electron gas (2DEG) concentration on the thickness of an InAs channel. It is found that electron mobility as high as 19050 cm2·V-1·s-1 has been achieved for an InAs channel of 22.5 nm. The Hall devices with high sensitivity and good temperature stability were fabricated based on the AlSb/InAs QW structures. Their sensitivity is markedly superior to Hall devices of InAs films. 相似文献
9.
GaAs/AlxGa1—xAs量子阱电极/非水溶液界面性能的研究 总被引:1,自引:0,他引:1
用阻抗谱研究了晶格匹配型单、多量子阱GaAs/AlxGa1-xAs电极在二茂铁乙腈溶液中的界面性能。得到了空间电荷层电容及表面态电容与电极电位的依赖关系。空间电荷电容与量子阱电极的结构有关,而表面态电容则决定于电极的表面性质如表面氧化层及二茂铁的吸附。分析和讨论了表面态的能级,密度的分布,来源和作用。 相似文献
10.
详细研究了有机发光二极管(OLED)在脉冲电压下的瞬态电流响应特性.瞬态响应电流由3部分组成:正向电流峰(IP)、稳态电流(IS)及反向电流峰(IN).研究发现IS为器件工作时通过器件的电流,而IN与IP则分别对应OLED器件电极/有机界面附近的空间电荷的形成及消失过程.IN、IP与脉冲电压成线性关系,阳极的费米能级与空穴传输材料的HOMO能级差导致IN大于IP.利用不同占空比的双脉冲电压研究了电流与空间电荷的关系,发现空间电荷的充分放电临界占空比只受界面接触的影响,而与器件内部结构无关. 相似文献