Electron leakage in GaAs-based separately confined heterostructure 808 nm laser diodes (SCH LDs) has a serious influence on device performance. Here, in order to reduce the energy of electrons injected into the quan...Electron leakage in GaAs-based separately confined heterostructure 808 nm laser diodes (SCH LDs) has a serious influence on device performance. Here, in order to reduce the energy of electrons injected into the quantum well (QW), an A1GaAs interlayer with a smaller A1 component is added between the active region and the n-side waveguide. Numerical device simulation reveals that when the Al-composition of the A1GaAs interlayer and its thickness are properly elected, the electron leakage is remarkably depressed and the characteristics of LDs are improved, owing to the reduction of injected electron energy and the improvement of QW capture efficiency.展开更多
In order to suppress the electron leakage to p-type region of near-ultraviolet GaN/In_xGa_(1-x )N/GaN multiple-quantumwell(MQW) laser diode(LD), the Al composition of inserted p-type AlxGa_(1-x)N electron bloc...In order to suppress the electron leakage to p-type region of near-ultraviolet GaN/In_xGa_(1-x )N/GaN multiple-quantumwell(MQW) laser diode(LD), the Al composition of inserted p-type AlxGa_(1-x)N electron blocking layer(EBL) is optimized in an effective way, but which could only partially enhance the performance of LD. Here, due to the relatively shallow GaN/In_(0.04)Ga_(0.96)N/GaN quantum well, the hole leakage to n-type region is considered in the ultraviolet LD. To reduce the hole leakage, a 10-nm n-type Al_xGa_(1-x)N hole blocking layer(HBL) is inserted between n-type waveguide and the first quantum barrier, and the effect of Al composition of Al_xGa_(1-x)N HBL on LD performance is studied. Numerical simulations by the LASTIP reveal that when an appropriate Al composition of Al_xGa_(1-x)N HBL is chosen, both electron leakage and hole leakage can be reduced dramatically, leading to a lower threshold current and higher output power of LD.展开更多
The typical light emission efficiency behaviors of InGaN/GaN multi-quantum well (MQW) blue light- emitting diodes (LEDs) grown on c-plane sapphire substrates are characterized by pulsed current operation mode in t...The typical light emission efficiency behaviors of InGaN/GaN multi-quantum well (MQW) blue light- emitting diodes (LEDs) grown on c-plane sapphire substrates are characterized by pulsed current operation mode in the temperature range 40 to 300 K. At temperatures lower than 80 K, the emission efficiency of the LEDs decreases approximately as an inverse square root relationship with drive current. We use an electron leakage model to explain such efficiency droop behavior; that is, the excess electron leakage into the p-side of the LEDs under high forward bias will significantly reduce the injection possibility of holes into the active layer, which in turn leads to a rapid reduction in the radiative recombination efficiency in the MQWs. Combining the electron leakage model and the quasi-neutrality principle in the p-type region, we can readily derive the inverse square root dependent function between the light emission efficiency and the drive current. It appears that the excess electron leakage into the p-type side of the LEDs is primarily responsible for the low-temperature efficiency droop behavior.展开更多
Electron leakage still needs to be solved for In Ga N-based blue-violet laser diodes(LDs), despite the presence of the electron blocking layer(EBL). To reduce further electron leakage, a new structure of In Ga N-b...Electron leakage still needs to be solved for In Ga N-based blue-violet laser diodes(LDs), despite the presence of the electron blocking layer(EBL). To reduce further electron leakage, a new structure of In Ga N-based LDs with an In Ga N interlayer between the EBL and p-type waveguide layer is designed. The optical and electrical characteristics of these LDs are simulated, and it is found that the adjusted energy band profile in the new structure can improve carrier injection and enhance the effective energy barrier against electron leakage when the In composition of the In Ga N interlayer is properly chosen. As a result, the device performances of the LDs are improved.展开更多
基金supported by the National Natural Science Foundation of China(Nos.61377020,61376089,61223005,61176126)the National Science Fund for Distinguished Young Scholars(No.60925017)
文摘Electron leakage in GaAs-based separately confined heterostructure 808 nm laser diodes (SCH LDs) has a serious influence on device performance. Here, in order to reduce the energy of electrons injected into the quantum well (QW), an A1GaAs interlayer with a smaller A1 component is added between the active region and the n-side waveguide. Numerical device simulation reveals that when the Al-composition of the A1GaAs interlayer and its thickness are properly elected, the electron leakage is remarkably depressed and the characteristics of LDs are improved, owing to the reduction of injected electron energy and the improvement of QW capture efficiency.
基金Project supported by the Science Challenge Project,China(Grant No.Z2016003)the National Key R&D Program of China(Grant Nos.2016YFB0400803and 2016YFB0401801)+1 种基金the National Natural Science Foundation of China(Grant Nos.61674138,61674139,61604145,61574135,61574134,61474142,61474110,61377020,and 61376089)the Beijing Municipal Science and Technology Project,China(Grant No.Z161100002116037)
文摘In order to suppress the electron leakage to p-type region of near-ultraviolet GaN/In_xGa_(1-x )N/GaN multiple-quantumwell(MQW) laser diode(LD), the Al composition of inserted p-type AlxGa_(1-x)N electron blocking layer(EBL) is optimized in an effective way, but which could only partially enhance the performance of LD. Here, due to the relatively shallow GaN/In_(0.04)Ga_(0.96)N/GaN quantum well, the hole leakage to n-type region is considered in the ultraviolet LD. To reduce the hole leakage, a 10-nm n-type Al_xGa_(1-x)N hole blocking layer(HBL) is inserted between n-type waveguide and the first quantum barrier, and the effect of Al composition of Al_xGa_(1-x)N HBL on LD performance is studied. Numerical simulations by the LASTIP reveal that when an appropriate Al composition of Al_xGa_(1-x)N HBL is chosen, both electron leakage and hole leakage can be reduced dramatically, leading to a lower threshold current and higher output power of LD.
基金supported by the National Natural Science Foundation of China(No.11074280)the Natural Science Foundation of Jiangsu Province,China(No.BK2012110)+3 种基金the Fundamental Research Funds for the Central Universities of China(No.JUSRP51323B)the Chinese Postdoctoral Science Foundation(No.2013M540437)the State Key Laboratory of ASIC and System(No.11KF003)the PAPD of Jiangsu Higher Education Institutions and the Summit of the Six Top Talents Program of Jiangsu Province(No.DZXX-053)
文摘The typical light emission efficiency behaviors of InGaN/GaN multi-quantum well (MQW) blue light- emitting diodes (LEDs) grown on c-plane sapphire substrates are characterized by pulsed current operation mode in the temperature range 40 to 300 K. At temperatures lower than 80 K, the emission efficiency of the LEDs decreases approximately as an inverse square root relationship with drive current. We use an electron leakage model to explain such efficiency droop behavior; that is, the excess electron leakage into the p-side of the LEDs under high forward bias will significantly reduce the injection possibility of holes into the active layer, which in turn leads to a rapid reduction in the radiative recombination efficiency in the MQWs. Combining the electron leakage model and the quasi-neutrality principle in the p-type region, we can readily derive the inverse square root dependent function between the light emission efficiency and the drive current. It appears that the excess electron leakage into the p-type side of the LEDs is primarily responsible for the low-temperature efficiency droop behavior.
基金supported by the National Natural Science Foundation of China(Nos.61474110,61377020,61376089,61223005,and 61176126)the National Science Fund for Distinguished Young Scholars(No.60925017)+1 种基金the One Hundred Person Project of the Chinese Academy of Sciencesthe Basic Research Project of Jiangsu Province(No.BK20130362)
文摘Electron leakage still needs to be solved for In Ga N-based blue-violet laser diodes(LDs), despite the presence of the electron blocking layer(EBL). To reduce further electron leakage, a new structure of In Ga N-based LDs with an In Ga N interlayer between the EBL and p-type waveguide layer is designed. The optical and electrical characteristics of these LDs are simulated, and it is found that the adjusted energy band profile in the new structure can improve carrier injection and enhance the effective energy barrier against electron leakage when the In composition of the In Ga N interlayer is properly chosen. As a result, the device performances of the LDs are improved.