Electroluminescence in metal-oxide-semiconductor tunnel diodes with a crystalline silicon/silicon dioxide quantum well

We investigated electroluminescence (EL) in metal-oxide-semiconductor (MOS) diodes with an indium tin oxide (ITO) film/ultrathin silicon dioxide (SiO2) film/ultrathin crystalline-silicon (Si) layer/buried SiO2 layer/Si substrate structure at a negative voltage applied to the ITO film. The EL peak shifted toward higher energy with decreasing Si-layer thickness. The dependence of the EL-peak energy on the Si-layer thickness shows that the EL is due to one-dimensional quantum confinement. Characterization of the MOS diodes suggested that electrons tunneling through the ultrathin SiO2 film from the conduction band (CB) of the ITO film are injected into higher energy states in the CB of the ultrathin Si layer with a negative voltage applied to the ITO film, and the tunneling electrons radiatively recombine with holes accumulated near the Si/SiO2 interface in the ultrathin Si layer.