We have succeeded in demonstrating zero-magnetic-field spin injection in metal-insulator-semiconductor (MIS) structure at room temperature using FePt/MgO/GaAs-based light-emitting diode heterojunction with out-of-plane magnetization. The spin polarization was investigated by spin-polarized electroluminescence (EL). The lower estimate injected at remanence was 1.5% and that injected at 1 T was reached up to 11.5%. The spin injection efficiency was estimated at least 29%. The bias dependence of the EL circular polarization showed that it decreases with increasing bias voltage for both at 1 T and at remanence.
We compared the electroluminescence (EL) polarization of two Fe∕MgO∕light-emitting-diode (LED) structures grown at different substrate temperatures for MgO growth: room temperature and 400°C. Two spin-LED wafers were prepared on molecular beam epitaxy grown LEDs by e-beam evaporation: one was LED∕MgO (RT)∕Fe (RT)∕Au cap (RT), and the other was LED∕MgO (400°C)∕Fe (150°C)∕Au cap (90°C). Spin-polarized EL was clearly observed in the latter sample, while the EL polarization was hardly observed in the former sample. The reasons for the near absence of EL polarization in the former sample are considered to be the degradation of the tunneling junction resulting from the crystallinity and the As-rich surface of the LED.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.