1-D and 2-D Nanocontacts for Reliable and Efficient Terahertz Photomixers
1-D and 2-D Nanocontacts for Reliable and Efficient Terahertz Photomixers
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DOI：
10.1109/tthz.2015.2399772
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发表时间：
2015-05-01
影响因子：
3.2
通讯作者：
Hartnagel, Hans L.
中科院分区：
文献类型：
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作者：
Al-Daffaie, Shihab;Yilmazoglu, Oktay;Hartnagel, Hans L.
在低温生长(LTG)和氮离子注入的GaAs上，利用一维和二维纳米接触制备了新型的连续波(CW)太赫兹(THz)光电探测器。一维和二维纳米接触分别由银纳米线和石墨烯片形成。物理直径为空集60 nm和120 nm的银纳米线(Ag-NW)可以处理分别为>；10和>；30 mA的电流，而不会发生电迁移，从而实现可靠的高光电流。在一维光电混合器中，这样的纳米线电极的小直径使器件电容比传统的叉指光电混合器减少了十倍以上。因此，这些纳米线特性可以用于制造截止频率为>；2太赫兹的光电混合器，并且具有极其可靠的操作。具有6-8层的多层石墨烯(MLG)具有独特的性能，具有高达9 mA/(10微米宽)的高短路电流能力和可靠的高光电流。此外，MLG只吸收2.3%的白光，是一种理想的透明纳米触头。这些石墨烯电极在2-D光电混合器中的使用允许高效的光功率照明以产生高光电流，并显示出可靠的连续太赫兹发射的潜力。最初的太赫兹测量证实了这些新的纳米接触光混合器的高可能性。
New types of continuous-wave (CW) terahertz (THz) photomixers were fabricated using 1-D and 2-D nanocontacts on low-temperature-grown (LTG) GaAs as well as nitrogen-ion-implanted GaAs. The 1-D and 2-D nanocontacts were formed by silver nanowires and graphene sheets, respectively. A silver nanowire (Ag-NW) with a physical diameter of empty set 60 nm and 120 nm can handle currents of > 10 and > 30 mA, respectively, without electromigration, thus enabling reliable high photocurrents. The small diameter of such a nanowire electrode in 1-D photomixers reduces the device capacitance by a factor of more than ten compared with photomixers with conventional interdigital fingers. Thus, these nanowire properties can be used for the fabrication of photomixers with cut-off frequencies > 2 THz and with extremely reliable operation. A multilayer graphene (MLG) of 6-8 layers shows unique properties with high short-circuit current capabilities of > 9 mA/(10 mu m width) and reliable high photocurrents. Furthermore, the MLG absorbs only 2.3% of white light and is ideal as a transparent nanocontact. The use of these graphene electrodes in 2-D photomixers allows an efficient optical power illumination for high photocurrent generation and shows the potential for reliable CW THz emission. Initial THz measurements confirmed the high possibilities of these new nanocontact photomixers.