The influences of growth techniques of AP-MOCVD GaAs/AlGaAs silicon-doped multi-quantum wells (MQWs), heterostructure bipolar transistors (HBTs), double barrier resonant tunneling diodes(DBRTDs) on their structures an...The influences of growth techniques of AP-MOCVD GaAs/AlGaAs silicon-doped multi-quantum wells (MQWs), heterostructure bipolar transistors (HBTs), double barrier resonant tunneling diodes(DBRTDs) on their structures and performances were studied. Continuously grown MQWs, that is, no growth interruption at the heterointerfaces, shown blue-shifted, narrower and stronger photoluminescence(PL) compared with interruptedly grown ones.TEM examination of the interrupted interfaces revealed a bright line corresponding to the compositional fluctuation and impurity adsorption, and indicated noncommutative structures of AlGaAs/GaAs and GaAs/AlGaAs interfaces. High performance HBTs and DBRTDs were obtained by continuously grown method while growth interruption caused performance degradation. It was concluded that growth interruption may cause accumulation of residua1 impurities in the ambient as well as compositional fluctuation while continuous growth at very low growth rates can overcome such problems.展开更多
In order to improve the characteristics of the general broad-waveguide 808-nm semiconductor laser diode （LD）, we design a new type quantum well LD with an asymmetric cladding structure. The structure is grown by met...In order to improve the characteristics of the general broad-waveguide 808-nm semiconductor laser diode （LD）, we design a new type quantum well LD with an asymmetric cladding structure. The structure is grown by metal organic chemical vapor deposition （MOCVD）. For the devices with 100-ttm-wide stripe and 1000-/zm-long cavity under continuous-wave （CW） operation condition, the typical threshold current is 190 mA, the slope efficiency is 1.31 W/A, the wall-plug efficiency reaches 63%, and the maximum output power reaches higher than 7 W. And the internal absorption value decreases to 1.5 cm^-1.展开更多
a.In-Sb alloys were grown on GaSb substrates by MOCVD at atmospheric pressure. TMGa, TMInand TMSb were used as reactants. Alloy solid competition , surface morphologies and electrical properties wereinvestigated. It...a.In-Sb alloys were grown on GaSb substrates by MOCVD at atmospheric pressure. TMGa, TMInand TMSb were used as reactants. Alloy solid competition , surface morphologies and electrical properties wereinvestigated. It was found that the growth temperature was a key parameter for optimized surface morphologyand crystalline quality of the Ga_zIn_1-Sb epilayers. The influence of growth temperature on the Ga solidcomposition was previously explained. The Ga solid composition was proportional to the Ga vapor compositionand vapor Ⅲ/V ratio, respectively . The Ga distribution as efficient was found to be 1. 22 under the optimizedgrowth parameters and decreased with decreasing growth temperature. The results of Hall measurements forGa.InSb alloys at room temperature show a P-type background doping. The hole mobility of the best samplewas 377 cm￣2/V s with a hole concentration of 7. 6 x 10￣16 cm￣(-3).展开更多
Quaternary Ga x In 1- x As 1- y Sb y alloys were grown on GaSb substrates by MOCVD using trimethylgallium, trimethylindium, trimethylantimony and dilutedarsine as the precursors. The dependence ...Quaternary Ga x In 1- x As 1- y Sb y alloys were grown on GaSb substrates by MOCVD using trimethylgallium, trimethylindium, trimethylantimony and dilutedarsine as the precursors. The dependence of the alloy′s compositions x and y (x,y >0.6) on the growth parameters were investigated. It was found that the Ga(Ⅲ) ratio and Sb(Ⅴ) ratio play a major role in determining x and y , respectively. An unusual effect of adding AsH 3 concentration in vapor phase on the Sb concentration in the solid for a constant value of Sb(Ⅴ) ratio is attributed to the effect of surface kinetics. The substrate temperature dependence of the compositions was described.展开更多
Highly oriented MgO(111)and MgO(100)thin films have been deposited on Si(111)and Si(100)substrates by using Low Pressure MOCVD(LPMOCVD).Magnesium 2,4-pentanedionate was used as the source ma- terial.The films have a v...Highly oriented MgO(111)and MgO(100)thin films have been deposited on Si(111)and Si(100)substrates by using Low Pressure MOCVD(LPMOCVD).Magnesium 2,4-pentanedionate was used as the source ma- terial.The films have a very smooth surface morphology and optical transparency with an index of refraction of 1.71(632.8 nm).Typical growth rate of the films is 1.0 μm/h.The data of X-ray diffraction analysis indi- cate that the films are fully textured with(111)and(100)orientation perpendicular to the substrate surface respectively.The main parameters having influence on the deposition are the substrate temperature,the total pressure in the reaction chamber,the reaction gases and its flowrate.展开更多
GaSb epilayers were grown on GaAs and/or GaSb substrates by MOCVD respectively.The influence of growth conditions on the properties of the epilayers was studied in order to improve the growth pro- cesses.The growth me...GaSb epilayers were grown on GaAs and/or GaSb substrates by MOCVD respectively.The influence of growth conditions on the properties of the epilayers was studied in order to improve the growth pro- cesses.The growth mechanism of MOCVD GaSb was investigated.An equation derived for chemical reac- tion controlled growth rate of MOCVD GaSb was verified by the experiments.The typical FWHM of doub- le crystal X-ray diffraction(DCXD)spectra of GaSb epilayers on GaSb and/or GaAs substrates are 20 arcsec and 150 arcsec,respectively.The 300 K hole concentration of p=1.2×10^(16)cm^(-3) with Hall mobility of 898 cm^2/V·s is obtained.展开更多
Superconducting thin films of YBa<sub>2</sub>Cu<sub>3</sub>O<sub>7-x</sub>（Y-Ba-Cu-O） with Tc more than 85K have been deposited in situ by metalorganic chemical vapor deposition ...Superconducting thin films of YBa<sub>2</sub>Cu<sub>3</sub>O<sub>7-x</sub>（Y-Ba-Cu-O） with Tc more than 85K have been deposited in situ by metalorganic chemical vapor deposition （MOCVD） on yttria stabilized zirconia（YSZ） substrates. The relationship of film orientation on substrate temperature and the lowest formation temperature region of superconducting phase have been obtained after changing the substrate temperature. The epitaxial relation between Y-Ba-Cu-O films and the YSZ su bstrates were discussed.展开更多
文摘The influences of growth techniques of AP-MOCVD GaAs/AlGaAs silicon-doped multi-quantum wells (MQWs), heterostructure bipolar transistors (HBTs), double barrier resonant tunneling diodes(DBRTDs) on their structures and performances were studied. Continuously grown MQWs, that is, no growth interruption at the heterointerfaces, shown blue-shifted, narrower and stronger photoluminescence(PL) compared with interruptedly grown ones.TEM examination of the interrupted interfaces revealed a bright line corresponding to the compositional fluctuation and impurity adsorption, and indicated noncommutative structures of AlGaAs/GaAs and GaAs/AlGaAs interfaces. High performance HBTs and DBRTDs were obtained by continuously grown method while growth interruption caused performance degradation. It was concluded that growth interruption may cause accumulation of residua1 impurities in the ambient as well as compositional fluctuation while continuous growth at very low growth rates can overcome such problems.
基金supported by the National Natural Science Foundation of China (No.50472068)the Program for New Century Excellent Talents in University
文摘In order to improve the characteristics of the general broad-waveguide 808-nm semiconductor laser diode （LD）, we design a new type quantum well LD with an asymmetric cladding structure. The structure is grown by metal organic chemical vapor deposition （MOCVD）. For the devices with 100-ttm-wide stripe and 1000-/zm-long cavity under continuous-wave （CW） operation condition, the typical threshold current is 190 mA, the slope efficiency is 1.31 W/A, the wall-plug efficiency reaches 63%, and the maximum output power reaches higher than 7 W. And the internal absorption value decreases to 1.5 cm^-1.
文摘a.In-Sb alloys were grown on GaSb substrates by MOCVD at atmospheric pressure. TMGa, TMInand TMSb were used as reactants. Alloy solid competition , surface morphologies and electrical properties wereinvestigated. It was found that the growth temperature was a key parameter for optimized surface morphologyand crystalline quality of the Ga_zIn_1-Sb epilayers. The influence of growth temperature on the Ga solidcomposition was previously explained. The Ga solid composition was proportional to the Ga vapor compositionand vapor Ⅲ/V ratio, respectively . The Ga distribution as efficient was found to be 1. 22 under the optimizedgrowth parameters and decreased with decreasing growth temperature. The results of Hall measurements forGa.InSb alloys at room temperature show a P-type background doping. The hole mobility of the best samplewas 377 cm￣2/V s with a hole concentration of 7. 6 x 10￣16 cm￣(-3).
文摘Quaternary Ga x In 1- x As 1- y Sb y alloys were grown on GaSb substrates by MOCVD using trimethylgallium, trimethylindium, trimethylantimony and dilutedarsine as the precursors. The dependence of the alloy′s compositions x and y (x,y >0.6) on the growth parameters were investigated. It was found that the Ga(Ⅲ) ratio and Sb(Ⅴ) ratio play a major role in determining x and y , respectively. An unusual effect of adding AsH 3 concentration in vapor phase on the Sb concentration in the solid for a constant value of Sb(Ⅴ) ratio is attributed to the effect of surface kinetics. The substrate temperature dependence of the compositions was described.
文摘Highly oriented MgO(111)and MgO(100)thin films have been deposited on Si(111)and Si(100)substrates by using Low Pressure MOCVD(LPMOCVD).Magnesium 2,4-pentanedionate was used as the source ma- terial.The films have a very smooth surface morphology and optical transparency with an index of refraction of 1.71(632.8 nm).Typical growth rate of the films is 1.0 μm/h.The data of X-ray diffraction analysis indi- cate that the films are fully textured with(111)and(100)orientation perpendicular to the substrate surface respectively.The main parameters having influence on the deposition are the substrate temperature,the total pressure in the reaction chamber,the reaction gases and its flowrate.
文摘GaSb epilayers were grown on GaAs and/or GaSb substrates by MOCVD respectively.The influence of growth conditions on the properties of the epilayers was studied in order to improve the growth pro- cesses.The growth mechanism of MOCVD GaSb was investigated.An equation derived for chemical reac- tion controlled growth rate of MOCVD GaSb was verified by the experiments.The typical FWHM of doub- le crystal X-ray diffraction(DCXD)spectra of GaSb epilayers on GaSb and/or GaAs substrates are 20 arcsec and 150 arcsec,respectively.The 300 K hole concentration of p=1.2×10^(16)cm^(-3) with Hall mobility of 898 cm^2/V·s is obtained.
文摘Superconducting thin films of YBa<sub>2</sub>Cu<sub>3</sub>O<sub>7-x</sub>（Y-Ba-Cu-O） with Tc more than 85K have been deposited in situ by metalorganic chemical vapor deposition （MOCVD） on yttria stabilized zirconia（YSZ） substrates. The relationship of film orientation on substrate temperature and the lowest formation temperature region of superconducting phase have been obtained after changing the substrate temperature. The epitaxial relation between Y-Ba-Cu-O films and the YSZ su bstrates were discussed.
