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Extremely low density self-assembled InAs/GaAs quantum dots

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Chinese Optics Letters 2008年第6期6卷 443-445页

作者：李林刘国军李占国李梅王晓华 national key laboratory of high power semiconductor lasers Changchun University of Science and Technology

The self-assembled InAs/GaAs quantum dots （QDs） with extremely low density of 8× 10^6 cm^-2 are achieved using higher growth temperature and lower InAs coverage by low-pressure metal-organic chemical vapour deposition （MOVCD）. As a result of micro-photoluminescence （micro-PL）, for extremely low density of 8 × 10^6 cm^-2 InAs QDs in the micro-PL measurements at 10 K, only one emission peak has been achieved. It is believed that the InAs QDs have a good potential to realize single photon sources.

关键词： InAs QDs GaAs Extremely low density self-assembled InAs/GaAs quantum dots

810-nm InGaAlAs/AlGaAs double quantum well semiconductor lasers with asymmetric waveguide structures

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Chinese Optics Letters 2008年第4期6卷 268-270页

作者：李林刘国军李占国李梅王晓华李辉万春明 national key laboratory of high power semiconductor lasers Changchun University of Science and Technology Changchun 130022

The 810-nm InGaAlAs/AlGaAs double quantum well （QW） semiconductor lasers with asymmetric waveguide structures, grown by molecular beam epitaxy, show high quantum efficiency and high-power conver- sion efficiency at continuous-wave （CW） power output. The threshold current density and slope efficiency of the device are 180 A/cm^2 and 1.3 W/A, respectively. The internal loss and the internal quantum efficiency are 1.7 cm^-1 and 93%, respectively. The 70% maximum power conversion efficiency is achieved with narrow far-field patterns.

关键词： GaAs well nm InGaAlAs/AlGaAs double quantum well semiconductor lasers with asymmetric waveguide structures

Preparation for Bragg grating of 808 nm distributed feedback laser diode

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Journal of semiconductors 2015年第5期36卷 54-57页

作者：王勇刘丹丹冯国庆叶镇高占琦王晓华 national key laboratory on high power semiconductor lasers Changchun University of Science and Technology

The second-order Bragg grating structure of an 808 nm distributed feedback semiconductor laser diode was designed and optimized. The grating with a period of 240 nm was fabricated on GaAs substrate by holographic photolithography and wet etching. Images of optical microscopy, scanning electron microscopy and atomic force microscopy show that the grating has a period of 240 nm, duty cycle of 0.25, depth of 80 nm, with perfect surface morphology, good fringe continuity and uniformity.

关键词： distributed feedback (DFB) laser diode (LD) grating holographic photolithography

Effect of Pt diffusion barrier layer in Ni/AuGe/Pt/Au on ohmic contact to n-GaAs

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Journal of semiconductors 2015年第3期36卷 141-143页

作者：王勇刘丹丹冯国庆叶镇高占琦王晓华 national key laboratory on high power semiconductor lasers Changchun University of Science and Technology

The multi-layer metals of Ni/AuGe/Pt/Au with a Pt diffusion barrier layer of ohmic contact to n-GaAs were studied. The surface morphology and ohmic contact resistivity of multi-layer metals were characterized, with and without the Pt diffusion barrier layer for comparison. The SEM and EDS measurements show the Pt diffusion barrier layer can block the interdiffusion of atoms in multi-layer metals, and improve the surface morphology. The TLM results show that the samples with a Pt diffusion barrier layer have uniform ohmic contact resistance, indicating that the Pt diffusion barrier layer can increase the repetition and uniformity of ohmic contact to n-GaAs, and improve the thermal stability and reliability of GaAs-based devices.

关键词： GaAs ohmic contact diffusion barrier layer

All-fiber erbium-doped dissipative soliton laser with multimode interference based on saturable-reserve saturable hybrid optical switch

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Chinese Physics B 2022年第6期31卷 435-439页

作者： Xin Zhao Renyan Wan Weiyan Li Liang Jin He Zhang Yan Li Yingtian Xu Linlin Shi Xiaohui Ma national key laboratory on high-power semiconductor lasers Changchun University of Science and TechnologyChangchun 130022China

Reverse saturable absorption is essential for the realization of dissipative *** this paper,we introduce reverse saturable absorption by using nonlinear multimode interference(NL-MMI),for the first time,to the best of our knowledge,and obtain a stable dissipative soliton *** adjusting the coupling efficiency from multimode fiber to single mode fiber,the absorption properties of NL-MMI can be switched between saturation and reverse *** dissipative soliton can be obtained with pulse width of 975 fs in the experiment,the 3-dB bandwidth at 1555 nm is 16 nm,and the maximum output power is 11.48 m *** nonlinear absorption optical modulation and high damage threshold characteristics of the NL-MMI based ultrafast optical switch provide a new idea for realizing dissipative solitons.

关键词： multimode interference laser mode-locking abnormal saturable absorption

Optical properties of 1.3-μm InAs/GaAs quantum dots grown by metal organic chemical vapor deposition

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Chinese Optics Letters 2009年第8期7卷 741-743页

作者：李林刘国军李占国李梅王晓华曲轶薄报学 national key Lab of high power semiconductor lasers Changchun University of Science and Technology

The optical properties of self-assembled InAs quantum dots （QDs） on GaAs substrate grown by metalorganic chemical vapor deposition （MOCVD） are reported. Photoluminescence （PL） measurements prove the good optical quality of InAs QDs, which axe achieved using lower growth temperature and higher InAs coverage. At room temperature, the ground state peak wavelength of PL spectrum and full-width at half-maximum （FWHM） are 1305 nm and 30 meV, respectively, which are obtained as the QDs are finally capped with 5-nm In0.06Ga0.94As strain-reducing layer （SRL）. The PL spectra exhibit two emission peaks at 1305 and 1198 nm, which correspond to the ground state （GS） and the excited state （ES） of the QDs, respectively.

关键词： Emission spectroscopy Gallium Gallium alloys Ground state Indium arsenide Industrial chemicals Metallorganic chemical vapor deposition Optical properties Organic chemicals Organometallics Semiconducting indium Vapors

Structural transitions of SWNT filled with C_(60) under high pressure

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Chinese Physics B 2016年第5期25卷 238-241页

作者：邹永刚徐莉田锟张贺马晓辉姚明光 national key laboratory of high power semiconductor lasers Changchun University of Science and Technology State key laboratory of Superhard Materials Jilin University

Raman spectra of C_（60） filled single-walled carbon nanotubes（C_（60）@SWNTs） with diameters of 1.3–1.5 nm have been studied under high pressure. A plateau in the pressure dependence of the G-band frequency at around 10 GPa was observed in both experiments with 514 nm and 830 nm excitation lasers, which is similar to the high pressure behaviors of pristine SWNTs. This structural transition has been assigned to the transformation into a peanut-like structure of the nanotubes. At pressure below 2 GPa, no obvious Raman signature related to the structural transition of nanotubes was observed, unlike what has been reported for C_（70） filled nanotubes. We discussed this point in terms of the arrangement differences of C_（60） and C_（70）molecules inside the nanotubes. At higher pressure up to 15 GPa, a graphite-like pressure evolution was observed in our C_（60）@SWNTs.

关键词： carbon nanotubes high pressure Raman spectra

Fabrication of high-power VCSEL with radial bridge electrodes

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Chinese Optics Letters 2009年第8期7卷 709-711页

作者：侯立峰钟钢赵英杰杨永庄王玉霞郝永芹冯源姜晓光谢浩瑞 national key laboratory on high power semiconductor lasers Changchun University of Science and Technology Armor Technique Institute of PLA

We report the fabrication of a novel high-power vertical-cavity surface-emitting laser （VCSEL） with radial bridge electrodes in this letter. The analysis shows that the radial bridge electrodes can reduce the p-type distributed Bragg reflector （p-DBR） electric and thermal resistance, and improve the device beam quality. The high-power radial brigde electrode VCSELs with 200-μm aperture have been made and tested. The testing results show that the differential resistance of the VCSEL is 0.43 Ω and the maximal continuouswave （CW） output power is 340 mW, 1.7 times higher than the conventional electrode device. Its thermal resistance is 0.095℃/mW, and its near-field pattern exhibits a homogeneous distribution. The high-power radial bridge electrode VCSEL has better temperature and opto-electric characteristics.

关键词： Bragg cells Electrodes lasers Optical waveguides

Growth and characterization of InAs quantum dots with low-density and long emission wavelength

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Chinese Optics Letters 2008年第1期6卷 71-73页

作者：李林刘国军李占国李梅王晓华 national key Lab of high power semiconductor lasers.Changchun University of Science and Technology

The growth parameters affecting the deposition of self-assembled InAs quantum dots （QDs） on GaAs substrate by low-pressure metal-organic chemical vapor deposition （MOCVD） are reported. The low-density InAs QDs （- 5 × 10^8cm^-2） are achieved using high growth temperature and low InAs coverage. Photoluminescence （PL） measurements show the good optical quality of low-density QDs. At room temperature, the ground state peak wavelength of PL spectrum and full-width at half-maximum （FWHM） are 1361 nm and 23 meV （35 nm）, respectively, which are obtained as the GaAs capping layer grown using triethylgallium （TEG） and tertiallybutylarsine （TBA）. The PL spectra exhibit three emission peaks at 1361, 1280, and 1204 nm, which correspond to the ground state, the first excited state, and the second excited state of the ODs, respectively.

关键词： InAs Growth and characterization of InAs quantum dots with low-density and long emission wavelength QDs