An exponential-doping structure is successfully applied to the preparation of AlGaAs/GaAs photocathodes through the metalorganic chemical vapor deposition(MOCVD)technique.The experimental results show that the quantum...An exponential-doping structure is successfully applied to the preparation of AlGaAs/GaAs photocathodes through the metalorganic chemical vapor deposition(MOCVD)technique.The experimental results show that the quantum efficiency in the entire waveband region for the exponential-doping photocathodes grown by MOCVD is remarkably enhanced as compared to those grown by molecular beam epitaxy.As a result of the improved built-in electric fields and cathode performance parameters,the photoemission characteristics for the MOCVD-grown transmission-mode and reflection-mode AlGaAs/GaAs photocathodes are different over the wavelength region of interest.展开更多
Strained InGaAs/GaAs quantum well (QW) was grown by low-pressuremetallorganic chemical vapor deposition (MOCVD). Growth interruption and strain buffer layer wereintroduced to improve the photoluminescence (PL) perform...Strained InGaAs/GaAs quantum well (QW) was grown by low-pressuremetallorganic chemical vapor deposition (MOCVD). Growth interruption and strain buffer layer wereintroduced to improve the photoluminescence (PL) performance of the InGaAs/GaAs quantum well. GoodPL results were obtained under condition of growth an interruption of 10 s combined with a moderatestrain buffer layer. Wavelength lasers of 1064 nm using the QW were grown and processed intodevices. Broad area lasers (100 μm x 500 μm) show very low threshold current densities (43 A/cm^2)and high slop efficiency (0.34 W/A, per facet).展开更多
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
基金the National Natural Science Foundation of China under Grant Nos 61067001,61240042 and 61261009the Key Science and Technology Project of Henan Province of China under Grant No 112102210202.
文摘An exponential-doping structure is successfully applied to the preparation of AlGaAs/GaAs photocathodes through the metalorganic chemical vapor deposition(MOCVD)technique.The experimental results show that the quantum efficiency in the entire waveband region for the exponential-doping photocathodes grown by MOCVD is remarkably enhanced as compared to those grown by molecular beam epitaxy.As a result of the improved built-in electric fields and cathode performance parameters,the photoemission characteristics for the MOCVD-grown transmission-mode and reflection-mode AlGaAs/GaAs photocathodes are different over the wavelength region of interest.
文摘Strained InGaAs/GaAs quantum well (QW) was grown by low-pressuremetallorganic chemical vapor deposition (MOCVD). Growth interruption and strain buffer layer wereintroduced to improve the photoluminescence (PL) performance of the InGaAs/GaAs quantum well. GoodPL results were obtained under condition of growth an interruption of 10 s combined with a moderatestrain buffer layer. Wavelength lasers of 1064 nm using the QW were grown and processed intodevices. Broad area lasers (100 μm x 500 μm) show very low threshold current densities (43 A/cm^2)and high slop efficiency (0.34 W/A, per facet).
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.
