Output power and reliability are the most important characteristic parameters of semiconductor lasers.However,catas-trophic optical damage(COD),which usually occurs on the cavity surface,will seriously damage the furt...Output power and reliability are the most important characteristic parameters of semiconductor lasers.However,catas-trophic optical damage(COD),which usually occurs on the cavity surface,will seriously damage the further improvement of the output power and affect the reliability.To improve the anti-optical disaster ability of the cavity surface,a non-absorption window(NAW)is adopted for the 915 nm InGaAsP/GaAsP single-quantum well semiconductor laser using quantum well mix-ing(QWI)induced by impurity-free vacancy.Both the principle and the process of point defect diffusion are described in detail in this paper.We also studied the effects of annealing temperature,annealing time,and the thickness of SiO_(2) film on the quan-tum well mixing in a semiconductor laser with a primary epitaxial structure,which is distinct from the previous structures.We found that when compared with the complete epitaxial structure,the blue shift of the semiconductor laser with the primary epi-taxial structure is larger under the same conditions.To obtain the appropriate blue shift window,the primary epitaxial struc-ture can use a lower annealing temperature and shorter annealing time.In addition,the process is less expensive.We also pro-vide references for upcoming device fabrication.展开更多
Built-in electric field may enhance or retard the impurity-free vacancy disordering (IFVD) during rapid thermal annealing (RTP) by imposing a drift on charged point defects. Built-in electric field is at the interface...Built-in electric field may enhance or retard the impurity-free vacancy disordering (IFVD) during rapid thermal annealing (RTP) by imposing a drift on charged point defects. Built-in electric field is at the interface between dielectric layer and top layer of the structure. Subsequent rapid thermal annealing leads to different intermixing results due to different field directions on InP cap layers in different doping types. Experimental results also show different influences of the built-in field on the two sublattices largely due to different charge numbers of point defects.展开更多
This work demonstrates the atomic vacancy effects on the phonon properties of armchair silicene nanoribbon in a step by step process for the first time.The phonon localization effect figures out the fact that vacancie...This work demonstrates the atomic vacancy effects on the phonon properties of armchair silicene nanoribbon in a step by step process for the first time.The phonon localization effect figures out the fact that vacancies cause to high-energy phonons become localized,whereas low-energy phonons can easily transmit.The vacancy reduces high-energy phonon transmission severely compared to low-energy phonon.It is also found from phonon density of states that high-frequency phonons soften towards the low-frequency region.The simulated phonon bandstructure verifies that most of the phonon branches transform to a nondegenerate state from a degenerate state and shifted toward a lower frequency regime due to the presence of vacancies.The overall consequences of atomic vacancies on the phonon thermal conductance disclose the reality that only a few atomic vacancies result in a vital reduction of phonon thermal conductance.In addition,the entropy of the disordered system is investigated.展开更多
Metal chalcogenide solid solution,especially ZnCdS,has been intensively investigated in photocatalytic H_(2) generation due to their cost-effective synthetic procedure and adjustable band structures.In this work,we re...Metal chalcogenide solid solution,especially ZnCdS,has been intensively investigated in photocatalytic H_(2) generation due to their cost-effective synthetic procedure and adjustable band structures.In this work,we report on the defect engineering of ZnCdS with surface disorder layer by simple room temperature Li-ethylenediamine(Li-EDA)treatment.Experimental results confirm the formation of unusual Zn and S dual vacancies,where rich S vacancies(Vs)served as electron trapping sites,meanwhile Zn vacancies(Vzn)served as hole trapping sites.The refined structure significantly facilitates the photo charge carrier transfer and improves photocatalytic properties of ZnCdS.The disordered ZnCdS shows a highest photocatalytic H_(2) production rate of 33.6 mmol·g^(-1)·h^(-1) under visible light with superior photocatalytic stabilities,which is 7.3 times higher than pristine ZnCdS and 7 times of Pt(1 wt.%)loaded ZnCdS.展开更多
The dependence of the microstructural change and lattice space symmetry of nano-SnO2 on the annealing temperature has been studied systematically using Raman spectroscopy and X-ray diffraction.Comparing the results of...The dependence of the microstructural change and lattice space symmetry of nano-SnO2 on the annealing temperature has been studied systematically using Raman spectroscopy and X-ray diffraction.Comparing the results of nano-SnO2 with the results of amorphous film and single crystal of SnO2 it is found that the new Raman peaks N1 and N2 are in accordance with Matossi’s force constant model completely.When the annealing temperature is near 673K,the local lattice disorders and the density of vacant lattice decrease rapidly in the nano-SnO2 grains.The lattice distortion and the new Raman peaks disappear almost at the same time.The possible mechanisms of the microstructural change and the new Raman peaks NI and N2 are discussed.展开更多
基金This work was supported by the National Natural Science Foundation of China(NNSFC)(Grant No.62174154).
文摘Output power and reliability are the most important characteristic parameters of semiconductor lasers.However,catas-trophic optical damage(COD),which usually occurs on the cavity surface,will seriously damage the further improvement of the output power and affect the reliability.To improve the anti-optical disaster ability of the cavity surface,a non-absorption window(NAW)is adopted for the 915 nm InGaAsP/GaAsP single-quantum well semiconductor laser using quantum well mix-ing(QWI)induced by impurity-free vacancy.Both the principle and the process of point defect diffusion are described in detail in this paper.We also studied the effects of annealing temperature,annealing time,and the thickness of SiO_(2) film on the quan-tum well mixing in a semiconductor laser with a primary epitaxial structure,which is distinct from the previous structures.We found that when compared with the complete epitaxial structure,the blue shift of the semiconductor laser with the primary epi-taxial structure is larger under the same conditions.To obtain the appropriate blue shift window,the primary epitaxial struc-ture can use a lower annealing temperature and shorter annealing time.In addition,the process is less expensive.We also pro-vide references for upcoming device fabrication.
基金supported by the National High-Tech Research and Development Program of China (Grant No. 2007AA313080)
文摘Built-in electric field may enhance or retard the impurity-free vacancy disordering (IFVD) during rapid thermal annealing (RTP) by imposing a drift on charged point defects. Built-in electric field is at the interface between dielectric layer and top layer of the structure. Subsequent rapid thermal annealing leads to different intermixing results due to different field directions on InP cap layers in different doping types. Experimental results also show different influences of the built-in field on the two sublattices largely due to different charge numbers of point defects.
文摘This work demonstrates the atomic vacancy effects on the phonon properties of armchair silicene nanoribbon in a step by step process for the first time.The phonon localization effect figures out the fact that vacancies cause to high-energy phonons become localized,whereas low-energy phonons can easily transmit.The vacancy reduces high-energy phonon transmission severely compared to low-energy phonon.It is also found from phonon density of states that high-frequency phonons soften towards the low-frequency region.The simulated phonon bandstructure verifies that most of the phonon branches transform to a nondegenerate state from a degenerate state and shifted toward a lower frequency regime due to the presence of vacancies.The overall consequences of atomic vacancies on the phonon thermal conductance disclose the reality that only a few atomic vacancies result in a vital reduction of phonon thermal conductance.In addition,the entropy of the disordered system is investigated.
基金supported by National Natural Science Foundation of China(Nos.21902104 and 21701135)Natural Science Foundation of Top Talent of SZTU(Nos.2019205,2019108101003,and 20200201)+2 种基金Foundation for Young Innovative Talents in Higher Education of Guangdong(No.2018KQNCX401)the Shenzhen Science and Technology Research Project(No.JCYJ20180508152903208)the Open Project Program of Key Laboratory for Analytical Science of Food Safety and Biology,Ministry of Education(No.FS2004).
文摘Metal chalcogenide solid solution,especially ZnCdS,has been intensively investigated in photocatalytic H_(2) generation due to their cost-effective synthetic procedure and adjustable band structures.In this work,we report on the defect engineering of ZnCdS with surface disorder layer by simple room temperature Li-ethylenediamine(Li-EDA)treatment.Experimental results confirm the formation of unusual Zn and S dual vacancies,where rich S vacancies(Vs)served as electron trapping sites,meanwhile Zn vacancies(Vzn)served as hole trapping sites.The refined structure significantly facilitates the photo charge carrier transfer and improves photocatalytic properties of ZnCdS.The disordered ZnCdS shows a highest photocatalytic H_(2) production rate of 33.6 mmol·g^(-1)·h^(-1) under visible light with superior photocatalytic stabilities,which is 7.3 times higher than pristine ZnCdS and 7 times of Pt(1 wt.%)loaded ZnCdS.
基金Project supported by the Foundation of State Science and Technology and the Natural Science Foundation of Anhui Province.
文摘The dependence of the microstructural change and lattice space symmetry of nano-SnO2 on the annealing temperature has been studied systematically using Raman spectroscopy and X-ray diffraction.Comparing the results of nano-SnO2 with the results of amorphous film and single crystal of SnO2 it is found that the new Raman peaks N1 and N2 are in accordance with Matossi’s force constant model completely.When the annealing temperature is near 673K,the local lattice disorders and the density of vacant lattice decrease rapidly in the nano-SnO2 grains.The lattice distortion and the new Raman peaks disappear almost at the same time.The possible mechanisms of the microstructural change and the new Raman peaks NI and N2 are discussed.
