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Ultrahigh-sensitivity far infrared photodetectors by using the quantum Hall effect

利用量子霍尔效应的超高灵敏度远红外光电探测器

基本信息

批准号：
09555108
负责人：
HIRAKAWA Kazuhiko
金额：
$ 5.7万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1999
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09555108/
关键词：
Teraherz radiation Far infrared detection Quantum Hall effect Semiconductor heterostructure Two-dimensional electrons Cyclotron resonance Landau levels Edge states テラヘルツ光遠赤外光半導体へテロ構造

项目摘要

When a two-dimensional electron system (2DES) is subjected to a strong magnetic field at low temperatures, the motion of electrons are completely quantized by cyclotron motion and O-dimensional like, equi-distant energy levels (Landau levels) are formed. In such a situation, a novel phenomenon called the quantum Hall effect appears. Although the quantum Hall effect (QHE) is most often applied to resistance standards, we are pursuing a possibility of using QHE for the detection of far infrared radiation (or sometimes called terahertz radiation). The major results of this project are ;(1) We have found that the diagonal resistance of the 2DES exhibits a very large photosensitivity in the vicinity of the quantum Hall states. From the analysis of the excitation spectra, it is clarified that the photosensitivity is induced by the cyclotron resonance absorption and that there are two mechanisms in the process, i. e., (i) electron heating due to photoabsorption and (ii) modulation of edge channel transport through potential redistribution by spatial separation of photoexcited electron and holes.(2) The responsivity of the QHE detector increases linearly with increasing the bias current and reaches 10ィイD17ィエD1 V/W, which is 1000 times larger than that of conventional bolometers. Further increase of the bias current results in the reduction in responsivity due to joule heating.(3) We have found that the dominant noise of the QHE detector is the 1/f noise and that it increases very quickly with increasing the bias current. Consequently, the maximum detectivity was obtained at relatively low bias currents (-μA).(4) The overall detectivity of the QHE photodetector was estimated to be 3x10ィイD113ィエD1 HzィイD11/2ィエD1cm/W, which is approximately 50 times larger than that of conventional bolometers. This high detectivity indicates the superiority of the QHE photodetector as a ultirahigh-sensitivity far infrared photodetector.

当二维电子系统（2DES）在低温下受到强磁场作用时，电子的运动被回旋运动完全量子化，形成了类似于0维的等距能级（朗道能级）。在这种情况下，一种叫做量子霍尔效应的新现象就出现了。虽然量子霍尔效应（QHE）最常应用于电阻标准，但我们正在寻求使用量子霍尔效应检测远红外辐射（或有时称为太赫兹辐射）的可能性。本项目的主要成果有：(1)我们发现2DES的对角线电阻在量子霍尔态附近表现出非常大的光敏性。从激发光谱分析可知，光敏性是由回旋共振吸收引起的，这一过程有两种机制，即(1)光吸收引起的电子加热和(2)光激发电子与空穴的空间分离通过势重分布调制边缘通道输运。(2)随着偏置电流的增大，QHE探测器的响应度呈线性增加，达到10 μ l μ l D17 μ l μ l D1 V/W，是传统测辐射热计的1000倍。由于焦耳加热，偏置电流的进一步增加导致响应率的降低。(3)我们发现QHE检测器的主导噪声是1/f噪声，并且随着偏置电流的增加，它的增加非常快。因此，在相对较低的偏置电流（-μA）下获得了最大的检测率。(4) QHE光电探测器的总探测率估计为3 × 10 μ m/ D113 μ m/ D1 Hz μ m/ D11/2 μ m/ D1cm/W，约为传统测辐射热计的50倍。这种高探测率表明了QHE光电探测器作为超高灵敏度远红外光电探测器的优越性。