Characterization Of GaSb Film And Supperlattices Grown By Molecular Beam Epitaxy

The lasers and detectors have some applications in mid-infrared spectral range, particularly in defense, medical treatment and telecommunications. There are several ways to obtain infrared light. Antimonide semiconductor laser emit mid-infrared spectrum. The most popular way to get the mid-infrared light is using antimonide as emitting active region, at present. The devlopment process is restricted for material grown on antimonide semiconductor laser. The lattice mismatch, defect density,stress and so on are inevitable in grown.Based on the above background, this paper focus on GaSb film and InAs/GaSb superlattice structures. The details of physical properties characterization of epitaxially grown on GaSb, thin film layer doping, passivation and interface control superlattice structure will be discussed.A homogeneous epitaxial film GaSb is grown on Molecular beam epitaxy (MBE). To overcome the large surface dislocation density, GaSb buffer layer is grown, which also reduces the roughness. The growth rate, Ⅴ/Ⅲ ratio beam source, grown temperature and other parameters are researched in the article. The crystal quality and optical properties of GaSb film is characterlized. The optimum growth parameters are measured, the half width is proved to be less than30arcsec in two crystal X ray diffraction. The lattice mismatch between the substrate layer and GaSb film is very small, it is optimized to achieve a homogeneous epitaxial purposes. The emission wavelength of GaSb film is1.99μm, only0.03eV on the half maximum with,which results that the crystal luminous quality is better, the crystal luminous quality is turned to be better as the emission wavelength of GaSb film is1.99μm and the half maximum is0.03eV.The doped is analyzed based on the film GaSb gorwn. High-temperature annealing treatment on GaSb film is picked up in experiment, which enhance the activity of an Sb atom, lower Ga antisite defect.so the carrier concentration is lower. By reducing the vacant site in the material, the integrity of the crystal lattice is improved. The results on Hall shows that GaSb film showes P-type conductivity and the N-type conductivity apparenty in different growth conditions, The concentration of hole and electron reaches1018cm-3,which statisfies the device character.A new passivation method is researched.which combines wet passivation methods with femtosecond laser irradiation GaSb. to reduce the state of the GaSb and improve optical properties. The surface of the sample forms a microstructure by femtosecond laser radiation. Through the spectrum expriments.we get the follow results:at room temperature. Photoluminescence spectra of the sample gets small blue shift of about14meV; at low temperature test, peak intensity becomes large,about781emV. So we can improve the GaSb optical properties by such a passive manner.How the growth interrupt method influences the interface structure of superlattices is researched by studing of InAs/GaSb superlattices structure that is grown by molecular beam epitaxy.As Sb atom and As atom are soaked in grown, the interface layer is formed for InAsSb. A high quality InAs/GaSb superlattice is abased on suit thickness and period, which is analyzed in detail. We put it out that peak half-width of50cycles symmetrical superlattice structure is98arcsec in X ray double crystal diffraction, stress is only0.43%; TEM shows the characterization between the buffer layer and the substrate.Photoluminescence spectra is concentrated in3.44μm, the mid-infrared spectral is achieved sucessfully.