Materials for new semiconductor lasers; atomically-controlled, growth of rare-earth-doped III-V semiconductors with high quality

点击翻译按钮获取中文摘要

Rare-earth (RE) doped semiconductors have gained significant attention as a promising new class of materials that emit light from the RE 4f shell by means of electrical injection, in which the energy of electron-hole pairs is transferred to the RE shell. The intra-4f shell transitions of RE ions give rise to sharp emission lines whose wavelengths are largely independent of both the host materials and temperature. This stability occurs because the filled outer 5s and 5p electron shells. screen transitions within the inner 4f electron shell from the interaction with the host. The intra-4f shell transitions from the first excited state (4^I_<13/2>) to the ground state (4^I_<15/2>) of Er^<3+> ions at around 1.5 μm is of special interest because the wavelength matches the minimum loss region of silica fibers used in optical communications.In this research project, we investigated atomically-controlled growth of Er-doped GaAs with high quality for new-type light-emitting devices. Results obt … More ained experimentally are summarized as follows1)By optimizing reactor structure and growth temperature, the abrupt change in composition at the heterointerface consisting of different group-V elements was successfully obtained.2)Er-20 configuration was selectively formed by codoping Er and O to GaAs, resulting in the increase in PL intensity by two orders in magnitude: The amount of O in growth ambient played an important role for the intensity increase.3)Er-related luminescence was observed in GaInP/GaAs : Er, O/GaAs doubleheterostructures by injecting, current at room temperature. The EL spectrum was dominated by Er-20 lines, suggesting a successful formation of the Er-20 center and a preferential excitation of the center by current injection.4)The current density dependence of the EL intensity revealed an extremely large excitation cross section of Er ions by current injection, approximately 10^<-15> cm^2. The large excitation cross section was confirmed by time-resolved measurements. of the EL intensity. It is by two orders in magnitude larger than that of Er-doped Si LEDs (6x10^<-17> cm^2). Less