摘要
The GalnAsSb quaternary alloys for 2～4 μm long wavelength optoelectronics have been prepared by MOCVD.The growth of buffer layers and the employment of GaSb/GaAs and GaSb/GaSb hybrid substrates are mentioned,which effectively improve the properties of GalnAsSb epilayers.In order to control the epitaxial growth of GaSb and GalnAsSb,emphasis is given on the deposition rates,growth temperatures and the relationship between growth conditions and the distribution coefficients of In and Sb.The experimen- tal solid compositions in this work are predicted by the thermodynamic calculations.Whether the growth of GalnAsSb epilayers is controlled by chemical reactions or by mass diffusions depends on growth temperatures. This argument is verified by kinetic considerations.The FWHMs of the DCXD (double crystal X-ray diffraction)spectra of GalnAsSb epilayers grown on GaSb/GaSb and GaSb/GaAs hybrid substrates are about 200～300 arcsec and 800 arcsec respectively.The unintentionally doped GalnAsSb epilayers have the mobilities of μp=100～240 cm^2/V·s at 300 K.The corresponding wavelength ofMOCVD GaInAsSb alloys is calculated from EPMA(electronic probe microanalysis)data and determined by FTIR(Fourier transformed infrared spectroscopy)measurement.
The GalnAsSb quaternary alloys for 2～4 μm long wavelength optoelectronics have been prepared by MOCVD.The growth of buffer layers and the employment of GaSb/GaAs and GaSb/GaSb hybrid substrates are mentioned,which effectively improve the properties of GalnAsSb epilayers.In order to control the epitaxial growth of GaSb and GalnAsSb,emphasis is given on the deposition rates,growth temperatures and the relationship between growth conditions and the distribution coefficients of In and Sb.The experimen- tal solid compositions in this work are predicted by the thermodynamic calculations.Whether the growth of GalnAsSb epilayers is controlled by chemical reactions or by mass diffusions depends on growth temperatures. This argument is verified by kinetic considerations.The FWHMs of the DCXD (double crystal X-ray diffraction)spectra of GalnAsSb epilayers grown on GaSb/GaSb and GaSb/GaAs hybrid substrates are about 200～300 arcsec and 800 arcsec respectively.The unintentionally doped GalnAsSb epilayers have the mobilities of μp=100～240 cm^2/V·s at 300 K.The corresponding wavelength ofMOCVD GaInAsSb alloys is calculated from EPMA(electronic probe microanalysis)data and determined by FTIR(Fourier transformed infrared spectroscopy)measurement.
