Light emission near 1.3 mu m using ITO-Al2O3-Si0.3Ge0.7-Si tunnel diodes

Abstract

We have fabricated Sn:In2O3 (ITO)-Al2O3 dielectric on Si1-xGex-Si metal-oxide-semiconductor tunnel diodes which emit light at around 1.3 mum, for x = 0.7. The emitted photon energy is smaller than the bandgap energy of Si, thus, avoiding strong light absorption by the Si substrate. The optical device structure is compatible with that of a metal-oxide-semiconductor field-effect transistor, since a conventional doped poly-Si gate electrode will be transparent to the emitted light. Increasing the Ge composition from 0.3 to 0.4 only slightly decreases the light-emitting efficiency.