Enhanced Room-Temperature 1.6 µm Electroluminescence from Si-Based Double-Heterostructure Light-Emitting Diodes Using Iron Disilicide

Abstract

We have fabricated Si/β-FeSi2/Si (SFS) double-heterostructure (DH) light-emitting diodes (LEDs) on Si(111) substrates with β-FeSi2 thickness ranging from 80 nm to 1 µm, and Si0.7Ge0.3/β-FeSi2/Si0.7Ge0.3(SGFSG) DH LEDs with a 200-nm-thick β-FeSi2 layer using lattice-matched Si0.7Ge0.3 layers by molecular-beam epitaxy. The electroluminescence (EL) peaked at an emission wavelength of approximately 1.6 µm at room temperature. As the thickness of the β-FeSi2 layer was increased in the SFS DH LEDs, the emission power of EL increased for a given current density J. EL with an emission power of over 0.4 mW and an external quantum efficiency of approximately 0.1% was achieved for the SFS DH LED with a 1-µm-thick β-FeSi2 layer. The smallest J value necessary for EL output, which is approximately 1 A/cm2, was achieved for the SGFSG DH LEDs.