The multi-element components of low alloy steel were quantified by using laser-induced breakdown spectroscopy (LIBS) in deep UV. The Nd:YAG pulsed laser was used to produce plasma. The spectrum was simultaneously obta...The multi-element components of low alloy steel were quantified by using laser-induced breakdown spectroscopy (LIBS) in deep UV. The Nd:YAG pulsed laser was used to produce plasma. The spectrum was simultaneously obtained by deep UV spectrometer. This paper studied the influence of experiment parameters on LIBS spectral intensity, such as delay, energy of laser, and the distance between the focusing lens and the surface of the sample. With the optimal expe- riment parameters, the characteristic lines of C, Ni, Si, Cr and Cu contained in low alloy steel were selected for quantit- ative analysis and the calibration curves of these elements were obtained. The linear correlation coefficient was good. Using the calibration curves to quantitative analysis for the sample 05-d, and the relative error of analytical results is less than 10% for most elements.展开更多
High-quality AlN layers with low-density threading dislocations are indispensable for high-efficiency deep ultraviolet light-emitting diodes（UV-LEDs）. In this work, a high-temperature AlN epitaxial layer was grown o...High-quality AlN layers with low-density threading dislocations are indispensable for high-efficiency deep ultraviolet light-emitting diodes（UV-LEDs）. In this work, a high-temperature AlN epitaxial layer was grown on sputtered AlN layer（used as nucleation layer, SNL） by a high-yield industrial metalorganic vapor phase epitaxy（MOVPE）. The full width half maximum（FWHM） of the rocking curve shows that the AlN epitaxial layer with SNL has good crystal quality. Furthermore, the relationships between the thickness of SNL and the FWHM values of（002） and（102） peaks were also studied. Finally, utilizing an SNL to enhance the quality of the epitaxial layer, deep UV-LEDs at 282 nm were successfully realized on sapphire substrate by the high-yield industrial MOVPE. The light-output power（LOP） of a deep UV-LED reaches 1.65 mW at 20 mA with external quantum efficiency of 1.87%. In addition, the saturation LOP of the deep UV-LED is 4.31 mW at an injection current of 60 mA. Hence, our studies supply a possible process to grow commercial deep UV-LEDs in high throughput industrial MOVPE, which can increase yield, at lower cost.展开更多
A 4×4 beta-phase gallium oxide(β-Ga_(2)O_(3))deep-ultraviolet(DUV)rectangular 10-fingers interdigital metalsemiconductor-metal(MSM)photodetector array of high photo responsivity is introduced.The Ga2O_(3)thin fi...A 4×4 beta-phase gallium oxide(β-Ga_(2)O_(3))deep-ultraviolet(DUV)rectangular 10-fingers interdigital metalsemiconductor-metal(MSM)photodetector array of high photo responsivity is introduced.The Ga2O_(3)thin film is prepared through the metalorganic chemical vapor deposition technique,then used to construct the photodetector array via photolithography,lift-off,and ion beam sputtering methods.The one photodetector cell shows dark current of 1.94 p A,phototo-dark current ratio of 6×10_(7),photo responsivity of 634.15 A·W^(-1),specific detectivity of 5.93×1011cm·Hz1/2·W^(-1)(Jones),external quantum efficiency of 310000%,and linear dynamic region of 108.94 d B,indicating high performances for DUV photo detection.Furthermore,the 16-cell photodetector array displays uniform performances with decent deviation of 19.6%for photo responsivity.展开更多
紫外LED的发光功率和效率还远不能令人们满意,波长短于300 nm的深紫外LED的发光效率普遍较低。厘清高Al组分Al Ga N多量子阱结构的发光机制将有利于探索改善深紫外LED的发光效率的新途径、新方法。为此,本文通过金属有机气相外延技术外...紫外LED的发光功率和效率还远不能令人们满意,波长短于300 nm的深紫外LED的发光效率普遍较低。厘清高Al组分Al Ga N多量子阱结构的发光机制将有利于探索改善深紫外LED的发光效率的新途径、新方法。为此,本文通过金属有机气相外延技术外延生长了表面平整、界面清晰可辨且陡峭的高Al组分AlGa N多量子阱结构材料,并对其进行变温光致发光谱测试,结合数值计算,深入探讨了Al Ga N量子阱的发光机制。研究表明,量子阱中具有很强的局域化效应,其发光和局域激子的跳跃息息相关,而发光的猝灭则与局域激子的解局域以及位错引起的非辐射复合有关。展开更多
文摘The multi-element components of low alloy steel were quantified by using laser-induced breakdown spectroscopy (LIBS) in deep UV. The Nd:YAG pulsed laser was used to produce plasma. The spectrum was simultaneously obtained by deep UV spectrometer. This paper studied the influence of experiment parameters on LIBS spectral intensity, such as delay, energy of laser, and the distance between the focusing lens and the surface of the sample. With the optimal expe- riment parameters, the characteristic lines of C, Ni, Si, Cr and Cu contained in low alloy steel were selected for quantit- ative analysis and the calibration curves of these elements were obtained. The linear correlation coefficient was good. Using the calibration curves to quantitative analysis for the sample 05-d, and the relative error of analytical results is less than 10% for most elements.
基金Project supported by the National Natural Sciences Foundation of China(Nos.61334009,61474109,61306050)
文摘High-quality AlN layers with low-density threading dislocations are indispensable for high-efficiency deep ultraviolet light-emitting diodes（UV-LEDs）. In this work, a high-temperature AlN epitaxial layer was grown on sputtered AlN layer（used as nucleation layer, SNL） by a high-yield industrial metalorganic vapor phase epitaxy（MOVPE）. The full width half maximum（FWHM） of the rocking curve shows that the AlN epitaxial layer with SNL has good crystal quality. Furthermore, the relationships between the thickness of SNL and the FWHM values of（002） and（102） peaks were also studied. Finally, utilizing an SNL to enhance the quality of the epitaxial layer, deep UV-LEDs at 282 nm were successfully realized on sapphire substrate by the high-yield industrial MOVPE. The light-output power（LOP） of a deep UV-LED reaches 1.65 mW at 20 mA with external quantum efficiency of 1.87%. In addition, the saturation LOP of the deep UV-LED is 4.31 mW at an injection current of 60 mA. Hence, our studies supply a possible process to grow commercial deep UV-LEDs in high throughput industrial MOVPE, which can increase yield, at lower cost.
基金Project supported by the National Natural Science Foundation of China(Grant No.61774019)Natural Science Research Start-up Foundation of Recruiting Talents of Nanjing University of Posts and Telecommunications(Grant Nos.XK1060921115 and XK1060921002)。
文摘A 4×4 beta-phase gallium oxide(β-Ga_(2)O_(3))deep-ultraviolet(DUV)rectangular 10-fingers interdigital metalsemiconductor-metal(MSM)photodetector array of high photo responsivity is introduced.The Ga2O_(3)thin film is prepared through the metalorganic chemical vapor deposition technique,then used to construct the photodetector array via photolithography,lift-off,and ion beam sputtering methods.The one photodetector cell shows dark current of 1.94 p A,phototo-dark current ratio of 6×10_(7),photo responsivity of 634.15 A·W^(-1),specific detectivity of 5.93×1011cm·Hz1/2·W^(-1)(Jones),external quantum efficiency of 310000%,and linear dynamic region of 108.94 d B,indicating high performances for DUV photo detection.Furthermore,the 16-cell photodetector array displays uniform performances with decent deviation of 19.6%for photo responsivity.
文摘紫外LED的发光功率和效率还远不能令人们满意,波长短于300 nm的深紫外LED的发光效率普遍较低。厘清高Al组分Al Ga N多量子阱结构的发光机制将有利于探索改善深紫外LED的发光效率的新途径、新方法。为此,本文通过金属有机气相外延技术外延生长了表面平整、界面清晰可辨且陡峭的高Al组分AlGa N多量子阱结构材料,并对其进行变温光致发光谱测试,结合数值计算,深入探讨了Al Ga N量子阱的发光机制。研究表明,量子阱中具有很强的局域化效应,其发光和局域激子的跳跃息息相关,而发光的猝灭则与局域激子的解局域以及位错引起的非辐射复合有关。
