Silicon defect and nanocrystal related white and red electroluminescence of Si-rich SiO₂ based metal-oxide-semiconductor diode

Silicon defect and nanocrystal related white and red electroluminescences (EL) of Si-rich SiO₂ based on metal-oxide-semiconductor (MOS) diode using transparent electrode contact are reported. The 500nm-thick Si-rich SiO₂ film on n-type Si substrate is synthesized using multi-recipe Si-ion-implantation or plasma enhanced chemical vapor deposition (PECVD). After 1100°C annealing for 3 hrs, the PL of Si-ion-implanted sample at 415 nm and 455 nm contributed by the weak-oxygen bond and neutral oxygen vacancy defects is observed. The white-light EL spectrum was observed at reverse bias, which originates from the tunneling and recombination intermediate state of SiO ₂:Si⁺ at a threshold current and voltage of 1.56 mA and 9.6 V, respectively. The maximum EL power of 110 nW is obtained at biased voltage of 25 V. The linear relationship between the optical power and injection current with a corresponding slope of 2.16 μW/A is obtained. The 4-nm nanocrystallite silicon (nc-Si) is precipitated in the 240nm-thick PECVD grown silicon-rich SiO₂ film annealed at 1100°C for 30 min with Indium-tin-oxide (ITO) of 0.8 mm in diameter, which contributes PL at 760 nm. The peak wavelength of the EL spectra coincides well with the PL. The threshold current and voltage are 86 V and 1.08 μA, respectively. The power-current (P-I) slope is determined as 697 μW/A. The carrier injection mechanism is dominated by Fowler-Nordheim(F-N) tunneling.