Near-infrared electroluminescence from metal-oxide-semiconductor devices with erbium-doped gadolinium oxide on silicon

Abstract

Metal-oxide semiconductor (MOS) devices with Er-doped gate oxides as the light-emitting layers are considered as one of the most promising strategies to achieve silicon-based electroluminescence (EL). In this work, Er-doped Gd2O3 (Gd2O3:Er) films were grown on silicon by atomic layer deposition. The main cubic Gd2O3 phase and hexagonal Gd9.33(SiO4)6O2 phase were obtained in Gd2O3:Er films after thermal annealing treatment. Moreover, 900 °C and 1100 °C were identified as the optimal annealing temperatures for the photoluminescence from Gd2O3 phase and Gd9.33(SiO4)6O2 phase films, respectively. Based on this, the MOS devices were further fabricated with annealed Gd2O3:Er films as the light-emitting layers. Analysis on the current-voltage characteristics of the MOS devices indicates that the electron transportation at the EL-enabling voltages is dominated by Fowler-Nordheim tunneling. More importantly, Er-related EL in the near-infrared region from MOS devices was detected at ∼1530 nm as a function of the Er dopant concentration. The external quantum efficiency reaches 4% for the 900 °C-annealed Gd2O3:0.47%Er MOS device and 8% for the 1100 °C-annealed Gd9.33(SiO4)6O2:2.97% Er MOS device. It is believed that this work has laid the foundation for developing near-infrared silicon-based emitters using Gd2O3:Er films.