Investigation of current injection in β-FeSi2/Si double-heterostructures light-emitting diodes by molecular beam epitaxy

The p-Si/p-β-FeSi2/p-Si/n-Si light-emitting diode (LED) was fabricated by molecular beam epitaxy (MBE) on Si(111) substrates. Compared to our previous p-Si/p-β-FeSi2/n-Si double heterostructures (DH) LED, the turn-on voltage in the current-voltage (I-V) characteristics increased by approximately 0.2 V, meaning that defect densities at around the p-n junction were reduced. However, Si-related EL (1.05 eV) became dominant unexpectedly, and thus EL of β-FeSi2 was suppressed accordingly. The origin of the luminescence is considered to be transitions via defect levels (1.05 eV) being due probably to Fe-B complex.