Photoluminescence of Nanocrystalline-Ge/SiN_x Multilayers
LI Cong;XU Yan-xin;HE Hong-ping;East China Research Institute of Electronic Engineering;National Laboratory of Solid State Microstructures;
Nanocrystalline-Ge(nc-Ge)/amorphous-SiN_x(a-SiN_x) multilayers( MLs) were fabricated by oxidizing hydrogenated amorphous-Ge(a-Ge∶ H)/a-SiN_x multilayers. Its strong photoluminescence(PL),peak at 500 nm,was observed at room temperature. Then,the mechanism of PL was studied,which indicated that the light emission was irrelevant to quantum confinement effect. The recombination of defects related to Si or N was also excluded. It is believed the PL of nc-Ge/SiN_x MLs is originated from the radiative recombination of tail states of oxidized a-SiN_x matrix,and the most effective excitation energy is close to the optical band gap of matrix.