Golyashov V A, Rusetsky V S, Shamirzaev T S, Dmitriev D V, Kislykh N V, Mironov A V, Aksenov V V, Tereshchenko O E
Rzhanov Institute of Semiconductor Physics, Siberian Branch, Russian Academy of Sciences, Novosibirsk 630090, Russian Federation; Novosibirsk State University, Novosibirsk, 630090, Russian Federation.
Rzhanov Institute of Semiconductor Physics, Siberian Branch, Russian Academy of Sciences, Novosibirsk 630090, Russian Federation; CJSC EKRAN-FEP, Novosibirsk 630060, Russian Federation.
Ultramicroscopy. 2020 Nov;218:113076. doi: 10.1016/j.ultramic.2020.113076. Epub 2020 Jul 17.
The circularly polarized cathodoluminescence (CL) technique has been used to study the free spin-polarized electron injection in semiconductor heterostructures with quantum wells (QWs). A polarized electron beam was created by the emission of optically oriented electrons from the p-GaAs(Cs,O) negative electron affinity (NEA) photocathode. The prepared beam was injected in a semiconductor QW target, which was activated by cesium and oxygen to reduce the work function. To study the spin-dependent injection, we developed a spin-detector prototype, which consists of a compact proximity focused vacuum tube with the source and target placed parallel to each other on the opposite ends of the vacuum tube (photodiode). The injection of polarized low-energy electrons into the target by varying the kinetic energy in the range of 0.5-5.0 eV and temperature in the range of 90-300 K was studied. The CL was polarized to 2 % by the injection of 20 % spin-polarized electron beam with the energy of 0.5 eV at room temperature. The asymmetry (Sherman function) of spin detection was estimated. It was shown that the dependence of the CL polarization degree on the injected electron energy is satisfactory described by the model that considers the electron spin relaxation in the heterostructure matrix and QWs. The results demonstrate that semiconductor detectors are promising for the spin-polarimetry applications based on the optical detection of free-electron spin polarization.
圆偏振阴极发光（CL）技术已被用于研究具有量子阱（QW）的半导体异质结构中的自由自旋极化电子注入。通过从p-GaAs（Cs，O）负电子亲和势（NEA）光电阴极发射光学取向电子来产生偏振电子束。将制备好的电子束注入到半导体量子阱靶中，该靶通过铯和氧激活以降低功函数。为了研究自旋相关注入，我们开发了一种自旋探测器原型，它由一个紧凑的近贴聚焦真空管组成，源和靶在真空管（光电二极管）的相对两端彼此平行放置。研究了通过在0.5 - 5.0 eV范围内改变动能以及在90 - 300 K范围内改变温度，将偏振低能电子注入到靶中的情况。在室温下，通过注入能量为0.5 eV的20%自旋极化电子束，CL的偏振度达到了2%。估计了自旋检测的不对称性（谢尔曼函数）。结果表明，考虑异质结构基体和量子阱中电子自旋弛豫的模型能够很好地描述CL偏振度对注入电子能量的依赖性。结果表明，基于自由电子自旋极化的光学检测，半导体探测器在自旋极化测量应用中具有广阔前景。
