Electroluminescent properties of a-SiO_x:H alloys

We report on a study of electroluminescence of p-i-n structures fabricated from a substoichiometric hydrogenated amorphous silicon-oxygen alloy with oxygen content ∼ 15 at.%. The devices exhibit a rectification ratio of four orders of magnitude and emit electroluminescence under forward bias. The electroluminescence external quantum efficiency at T = 295 K is of the order of 10^-6%. Analysis of thermal quenching of photoluminescence and electroluminescence in the temperature range 100-480 K, combined with picosecond optical pump and probe measurements, indicate contributions of molecular-like silicon structures and of electron-hole recombination in the band tail states to the process of light emission at room temperature.