Terahertz emission from two-dimensional plasmons in semiconductor heterostructures

半导体异质结构中二维等离子体激元的太赫兹发射

• 批准号: 06555003
• 负责人: HIRAKAWA Kazuhiko
• 金额: $ 4.03万
• 依托单位: University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (A)
• 财政年份: 1994
• 资助国家: 日本
• 起止时间: 1994 至 1996
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-06555003/
• 关键词: two-dimensional electron; Plasma oscillation; Gallium Arsenide; heterostructure; teraherz; femtosecond; 極短寿命光伝導体; 光伝導ダイポールアンテナ; テラヘルツ光; 遠赤外光; 半導体ヘテロ構造; プラズモン; ホットエレクトロン; ガリウムム素; ダイポールアンテナ

The radiative decay of grating-coupled two-dimensional (2D) plasmons in semiconductor heterostructures is one of promising candidates for tunable solid-state terahertz (THz) radiation sources. We have investigated the excitation relaxation mechanisms of 2D plasmons in AlGaAa/GaAs heterostructures by cw and time-resolved THz emission spectroscopy.By using a combination of a broadband THz detector and a magnetic-field tuned cyclotron resonance (CR) filter, we can determine the spectral line shape as well as the intensity of the radiation due to 2D plasmons. Spectroscopic measurement clearly resolved narrow emission peaks due to 2D plasmons. The observed emission energies are in good agreement with theory. The plasmon emission intensity is found to increase with increasing electrical input power to the electron system and follow the Bose-Einstein distribution law characterized by the thermodynamic temperature of the hot 2D electron system, indicating the thermal excitation of 2D plasmons inthe present experimental regime.Furthermore, the excitation of 2D plasmons in AlGaAs/GaAs heterostructures has been investigated by timeresolved THz emission spectroscopy. Coherent submillimeter-wave emission from nonequilibrium free carrier plasma oscillations created by femtosecond laser pulse illumination has been observed for the first time. The observed spectral linewidths are found to be much broader than those observed in a cw THz absorption spectroscopy. Thus, the relaxation is much faster than the momentum relaxation, suggesting the importance of the dephasing process due to the smallangle impurity scattering.

半导体异质结构中光栅耦合二维等离子体激元的辐射衰减是可调谐固态太赫兹辐射源的一个很有前途的候选者。利用连续波和时间分辨THz发射光谱技术研究了AlGaAa/GaAs异质结中二维等离子体激元的激发弛豫机制，利用宽带THz探测器和磁场调谐的回旋共振（CR）滤波器，我们可以确定二维等离子体激元的谱线形状和辐射强度。光谱测量清楚地解决了由于2D等离子体激元的窄发射峰。观测到的发射能量与理论符合得很好。等离子体激元的发射强度随电子系统输入功率的增加而增加，并遵循玻色-爱因斯坦分布规律，表明在本实验条件下存在热激发的二维等离子体激元.首次观测到飞秒激光脉冲照射产生的非平衡自由载流子等离子体振荡产生的相干亚毫米波辐射。所观察到的光谱线宽被发现是更广泛的比在连续太赫兹吸收光谱中观察到的。因此，弛豫比动量弛豫快得多，表明由于小角度杂质散射的退相过程的重要性。

项目成果

K.Hirakawa, I.Wilke, K.Yamanaka, H.G.Roskos, M.Vosseburger: "Coherent submillimeter-wave emission from non-equilibrium two-dimensional free carrier plasmas in AlGaAs/GaAs heterojunctions" Surface Science. vol. 361/362. (1996)

K.Hirakawa、I.Wilke、K.Yamanaka、H.G.Roskos、M.Vosseburger：“AlGaAs/GaAs 异质结中非平衡二维自由载流子等离子体的相干亚毫米波发射”表面科学。

K.Hirakawa, Y.Shimada, and T.Ikoma: "Supply-function dependent sequential resonant tunneling in semiconductor multiple quantum well diodes" Physica B. vol. 227. (1996)

K.Hirakawa、Y.Shimada 和 T.Ikoma：“半导体多量子阱二极管中依赖于电源函数的顺序谐振隧道”Physica B. vol。

N.Sekine, K.Hirakawa, F.Sogawa, Y.Arakawa, N.Usami, Y.: "Ultrashort lifetime photocarriers in Ge thin films" Applied Physics Letters. 68-24. (1996)

N.Sekine、K.Hirakawa、F.Sogawa、Y.Arakawa、N.Usami、Y.：“Ge 薄膜中的超短寿命光载流子”应用物理快报。

J.J.Heremans: "Mobility anisotropy of two-dimensional hole systems in(311)A GaAs/AlGaAs heterojunctions" Journal of Applied Physics. 76. 1980-1982 (1994)

J.J.Heremans：“(311)A GaAs/AlGaAs 异质结中二维空穴系统的迁移率各向异性”应用物理学杂志。

S.-N.Wang, K.Yamanaka, K.Hirakawa, M.Noguchi and T.Ikoma: "Direct determination of bare confinement potentials in AlGaAs/GaAs split-gate single quantum wires by far infrared spectroscopy" Japanese Journal of Applied Physics (Part 2). vol. 35-10A. (1996)

S.-N.Wang、K.Yamanaka、K.Hirakawa、M.Noguchi 和 T.Ikoma：“通过远红外光谱直接测定 AlGaAs/GaAs 分栅单量子线中的裸约束势” 日本应用物理学杂志