Optical reflection anisotropy microscopy mappings of micropipe defects on the surface of a 4H-SiC single crystal are studied by the scanning anisotropy microscopy(SAM)system.The reflection anisotropy(RA)image with a&#...Optical reflection anisotropy microscopy mappings of micropipe defects on the surface of a 4H-SiC single crystal are studied by the scanning anisotropy microscopy(SAM)system.The reflection anisotropy(RA)image with a'butterfly pattern'is obtained around the micropipes by SAM.The RA image of the edge dislocations is theoretically simulated based on dislocation theory and the photoelastic principle.By comparing with the Raman spectrum,it is verified that the micropipes consist of edge dislocations.The different patterns of the RA images are due to the different orientations of the Burgers vectors.Besides,the strain distribution of the micropipes is also deduced.One can identify the dislocation type,the direction of the Burgers vector and the optical anisotropy from the RA image by using SAM.Therefore,SAM is an ideal tool to measure the optical anisotropy induced by the strain field around a defect.展开更多
Commercially available AlGaN/GaN high-electron-mobility transistors(HEMTs)are beginning to enter the public scene froma range of suppliers.Based on previous studies,commercial GaN-based electronics are expected to be ...Commercially available AlGaN/GaN high-electron-mobility transistors(HEMTs)are beginning to enter the public scene froma range of suppliers.Based on previous studies,commercial GaN-based electronics are expected to be tolerant to different types of irradiation in space.To test this assumption,we compared the characteristic electrical curves obtained at different X-ray irradiation doses for GaN HEMT devices manufactured by Infineon and Transphorm.The p-GaN-based device was found to be more robust with a stable threshold voltage,whereas the threshold voltage of the device with ametal-insulator-semiconductor gatewas found to shift first in the negative and then the positive direction.This dynamic phenomenon is caused by the releasing and trapping effects of radiation-induced charges in the dielectric layer and at the interface of irradiated devices.As such,the p-GaNgate-based GaN HEMT provides a promising solution for use as an electric source in space.展开更多
This letter presents the fabrication of InP double heterojunction bipolar transistors(DHBTs)on a 3-inch flexible substrate with various thickness values of the benzocyclobutene(BCB)adhesive bonding layer,the correspon...This letter presents the fabrication of InP double heterojunction bipolar transistors(DHBTs)on a 3-inch flexible substrate with various thickness values of the benzocyclobutene(BCB)adhesive bonding layer,the corresponding thermal resistance of the InP DHBT on flexible substrate is also measured and calculated.InP DHBT on a flexible substrate with 100 nm BCB obtains cut-off frequency f_(T)=358 GHz and maximum oscillation frequency f_(MAX)=530 GHz.Moreover,the frequency performance of the InP DHBT on flexible substrates at different bending radii are compared.It is shown that the bending strain has little effect on the frequency characteristics(less than 8.5%),and these bending tests prove that InP DHBT has feasible flexibility.展开更多
Building communication links among multiple users in a scalable and robust way is a key objective in achieving large-scale quantum networks.In a realistic scenario,noise from the coexisting classical light is inevitab...Building communication links among multiple users in a scalable and robust way is a key objective in achieving large-scale quantum networks.In a realistic scenario,noise from the coexisting classical light is inevitable and can ultimately disrupt the entanglement.The previous significant fully connected multiuser entanglement distribution experiments are conducted using dark fiber links,and there is no explicit relation between the entanglement degradations induced by classical noise and its error rate.Here,a semiconductor chip with a high figure-of-merit modal overlap is fabricated to directly generate broadband polarization entanglement.The monolithic source maintains the polarization entanglement fidelity of above 96%for 42 nm bandwidth,with a brightness of 1.2×10^(7)Hz mW^(−1).A continuously working quantum entanglement distribution are performed among three users coexisting with classical light.Under finite-key analysis,secure keys are established and images encryption are enabled as well as quantum secret sharing between users.This work paves the way for practical multiparty quantum communication with integrated photonic architecture compatible with real-world fiber optical communication network.展开更多
In this Letter,we reported the preliminary results of an integrating periodically capacitive-loaded traveling wave electrode(CL-TWE)Mach–Zehnder modulator(MZM)based on InP-based multiple quantum well(MQW)optical wave...In this Letter,we reported the preliminary results of an integrating periodically capacitive-loaded traveling wave electrode(CL-TWE)Mach–Zehnder modulator(MZM)based on InP-based multiple quantum well(MQW)optical waveguides.The device configuration mainly includes an optical Mach–Zehnder interferometer,a direct current electrode,two phase electrodes,and a CL-TWE consisting of a U electrode and an I electrode.The modulator was fabricated on a 3 in.InP epitaxial wafer by standard photolithography,inductively coupled plasma dry etching,wet etching,electroplating,etc.Measurement results show that the MZM exhibits a3 dB electro-optic bandwidth of about 31 GHz,a Vπof 3 V,and an extinction ratio of about 20 dB.展开更多
基金Project supported by the National Key Research and Development Program of China(Grant Nos.2018YFE0204001,2018YFA0209103,2016YFB0400101,and 2016YFB0402303)the National Natural Science Foundation of China(Grant Nos.61627822,61704121,61991430,and 62074036)Postdoctoral Research Program of Jiangsu Province(Grant No.2021K599C).
文摘Optical reflection anisotropy microscopy mappings of micropipe defects on the surface of a 4H-SiC single crystal are studied by the scanning anisotropy microscopy(SAM)system.The reflection anisotropy(RA)image with a'butterfly pattern'is obtained around the micropipes by SAM.The RA image of the edge dislocations is theoretically simulated based on dislocation theory and the photoelastic principle.By comparing with the Raman spectrum,it is verified that the micropipes consist of edge dislocations.The different patterns of the RA images are due to the different orientations of the Burgers vectors.Besides,the strain distribution of the micropipes is also deduced.One can identify the dislocation type,the direction of the Burgers vector and the optical anisotropy from the RA image by using SAM.Therefore,SAM is an ideal tool to measure the optical anisotropy induced by the strain field around a defect.
基金Thisworkwas supported by the National Key R&D Programof China(No.2017YFB0402800,2017YFB0402802).
文摘Commercially available AlGaN/GaN high-electron-mobility transistors(HEMTs)are beginning to enter the public scene froma range of suppliers.Based on previous studies,commercial GaN-based electronics are expected to be tolerant to different types of irradiation in space.To test this assumption,we compared the characteristic electrical curves obtained at different X-ray irradiation doses for GaN HEMT devices manufactured by Infineon and Transphorm.The p-GaN-based device was found to be more robust with a stable threshold voltage,whereas the threshold voltage of the device with ametal-insulator-semiconductor gatewas found to shift first in the negative and then the positive direction.This dynamic phenomenon is caused by the releasing and trapping effects of radiation-induced charges in the dielectric layer and at the interface of irradiated devices.As such,the p-GaNgate-based GaN HEMT provides a promising solution for use as an electric source in space.
基金National Natural Science Foundation of China under Grants 61875241.
文摘This letter presents the fabrication of InP double heterojunction bipolar transistors(DHBTs)on a 3-inch flexible substrate with various thickness values of the benzocyclobutene(BCB)adhesive bonding layer,the corresponding thermal resistance of the InP DHBT on flexible substrate is also measured and calculated.InP DHBT on a flexible substrate with 100 nm BCB obtains cut-off frequency f_(T)=358 GHz and maximum oscillation frequency f_(MAX)=530 GHz.Moreover,the frequency performance of the InP DHBT on flexible substrates at different bending radii are compared.It is shown that the bending strain has little effect on the frequency characteristics(less than 8.5%),and these bending tests prove that InP DHBT has feasible flexibility.
基金supported by the National Natural Science Foundation of China(Grant No.12274233,12174187,62288101)Cheng Qian acknowledges financial support from the Postgraduate Research&Practice Innovation Program of Jiangsu Province(SJCX23_0569).
文摘Building communication links among multiple users in a scalable and robust way is a key objective in achieving large-scale quantum networks.In a realistic scenario,noise from the coexisting classical light is inevitable and can ultimately disrupt the entanglement.The previous significant fully connected multiuser entanglement distribution experiments are conducted using dark fiber links,and there is no explicit relation between the entanglement degradations induced by classical noise and its error rate.Here,a semiconductor chip with a high figure-of-merit modal overlap is fabricated to directly generate broadband polarization entanglement.The monolithic source maintains the polarization entanglement fidelity of above 96%for 42 nm bandwidth,with a brightness of 1.2×10^(7)Hz mW^(−1).A continuously working quantum entanglement distribution are performed among three users coexisting with classical light.Under finite-key analysis,secure keys are established and images encryption are enabled as well as quantum secret sharing between users.This work paves the way for practical multiparty quantum communication with integrated photonic architecture compatible with real-world fiber optical communication network.
文摘In this Letter,we reported the preliminary results of an integrating periodically capacitive-loaded traveling wave electrode(CL-TWE)Mach–Zehnder modulator(MZM)based on InP-based multiple quantum well(MQW)optical waveguides.The device configuration mainly includes an optical Mach–Zehnder interferometer,a direct current electrode,two phase electrodes,and a CL-TWE consisting of a U electrode and an I electrode.The modulator was fabricated on a 3 in.InP epitaxial wafer by standard photolithography,inductively coupled plasma dry etching,wet etching,electroplating,etc.Measurement results show that the MZM exhibits a3 dB electro-optic bandwidth of about 31 GHz,a Vπof 3 V,and an extinction ratio of about 20 dB.
