| GaInSb and GaAlSb crystals,as typical III-V compound semiconductor materials,are widely used in infrared detection,lidar,photovoltaic power generation,integrated circuits,navigation and tracking and other scientific and technological frontier fields due to their unique advantages of high electron mobility and narrow band gap.However,the structure and properties of GaInSb crystal have not been significantly improved due to the large composition segregation of In element in GaInSb crystal and many dislocations and microcracks in the prepared crystal.As for GaAlSb crystals,most of them are prepared by epitaxial growth technology.Epitaxial growth technology has certain critical dimension requirements for thin layer thickness,and also has certain limitations for large-size crystal preparation and industrial production.In addition,the development and application of GaAlSb crystal are severely restricted by factors such as the matching of thermal expansion coefficient and chemical stability among epitaxial layer,buffer layer and substrate,the difficulty of preparing substrate materials and the cost.In this paper,GaSb crystal,GaAlSb crystal and GaInSb:Al crystal were grown by vertical bridgman method.the effects of a certain amount of Al doping on the structure and properties of GaSb crystal,GaAlSb crystal and GaInSb:Al crystal were studied.X-ray diffractometer(XRD),energy dispersive spectrometer(EDS),metallographic microscope,Hall effect tester and Fourier transform infrared spectrometer were used to test and characterize the structure and properties of the crystal.The main conclusions of this paper are as follows:(1)GaSb crystal,Ga1-xAlxSb crystal,Ga0.86In0.14Sb crystal and Ga0.86In0.14Sb:Al crystal(?25 mm×100 mm)grown by vertical bridgman method.(2)The segregation of Al component in GaAlSb crystal prepared in this experiment is very low,with the minimum radial segregation of 0.065 mol%/mm and the minimum axial segregation of 0.008 mol%/mm.(3)The segregation of In component in GaInSb crystal prepared in this experiment is very low.The minimum radial segregation of indium component can reach 0.045 mol%/mm,and the minimum axial segregation can reach 0.052mol%/mm.(4)In a certain doping range,with the increase of Al content,the dislocation density of the ingot is obviously improved,and the distribution tends to be uniform gradually.The dislocation density of GaAlSb crystal decreases from 3.634×103 cm-2to 1.256×103 cm-2.The dislocation density of Ga0.86In0.14Sb:Al crystal decreased from3.431×104 cm-2 to 2.461×103 cm-2.(5)Al is used as the isoelectronic doping of Ga,which makes the P-type GaSb crystal with holes as the main carrier become the N-type GaAlSb crystal with free electrons as the main carrier,increasing the concentration of electrons as the main carrier,improving the electron mobility to 2.140×103 cm2/(V·s)and reducing the resistivity to 1.416×10-3?·cm.(6)As the isoelectronic doping of Ga and In,Al not only increases the number of electrons as the main carrier,but also increases the mobility of each component.The electron mobility of GaInSb crystal increases to 1.982×103 cm2/(V·s),and the resistivity decreases to 1.261×10-3?·cm. |
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