Room temperature magneto-optic effect in silicon light-emitting diodes

Abstract

In weakly spin–orbit coupled materials, the spin-selective nature of recombination can give rise to large magnetic-field effects, e.g. on the electro-luminescence of molecular semiconductors. Although silicon has weak spin–orbit coupling, observing spin-dependent recombination through magneto-electroluminescence is challenging: silicon’s indirect band-gap causes an inefficient emission and it is difficult to separate spin-dependent phenomena from classical magneto-resistance effects. Here we overcome these challenges and measure magneto-electroluminescence in silicon light-emitting diodes fabricated via gas immersion laser doping. These devices allow us to achieve efficient emission while retaining a well-defined geometry, thus suppressing classical magnetoresistance effects to a few percent. We find that electroluminescence can be enhanced by up to 300% near room temperature in a seven Tesla magnetic field, showing that the control of the spin degree of freedom can have a strong impact on the efficiency of silicon LEDs.

Magnetic field effect in organic light-emitting diodes based on Co spin polarization source

“…研究者对探索与电子自旋属性相关 的物理机制产生了浓厚兴趣. 2018年, Chiodi等人 [7] 报 道了气浸硅发光二极管的磁致电致发光效应, 将经典 磁阻效应抑制到几个百分点, 发现在室温附近, 外加 磁场为7 T时, 器件的电致发光能提高3倍. 2019年, Is-lam等人 [8] 报道了无机半导体CaAs的自旋注入与探测, 并且在低温环境下测量了器件电子自旋的注入效率, 发现77和1.5 K的温度下, 自旋电子注入效率分别是 2.5%和1.6%.…”

Model for large magnetoresistance effect in p–n junctions

“…According to the inhomogeneity MR mechanism, the conventional p-n junction device can also be considered as a perfect system to obtain a large MR effect. [29][30][31][32] This is because the p-n junction takes advantage of the bipolar (electron and hole) nature of transport in an inhomogeneously doped semiconductor. The opposite sign of the carrier mobility between the electron and the hole can increase the fluctuation of the carrier mobility, which effectively enhances the MR effect.…”