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

TL;DR

This paper demonstrates a significant room-temperature magneto-electroluminescence effect in silicon LEDs, showing that magnetic fields can substantially enhance silicon light emission by controlling spin-dependent recombination.

Contribution

The study introduces a novel silicon LED fabrication method enabling efficient emission and clear observation of magneto-electroluminescence at room temperature, overcoming previous challenges.

Findings

Electroluminescence increased by up to 300% in a 7 Tesla magnetic field.

Achieved efficient silicon LED emission with suppressed classical magnetoresistance effects.

Observed strong spin-dependent effects influencing silicon light emission at room temperature.

Abstract

In weakly spin-orbit coupled materials, the spin-selective nature of recombination can give rise to large magnetic-field effects, for example on electro-luminescence from molecular semiconductors. While silicon has weak spin-orbit coupling, observing spin-dependent recombination through magneto-electroluminescence is challenging due to the inefficiency of emission due to silicon's indirect band-gap, and to the difficulty in separating spin-dependent phenomena from classical magneto-resistance effects. Here we overcome these challenges to 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.