We demonstrate the use of an infrared modulated photoluminescence(PL)method based on a step-scan Fourier-transform infrared spectrometer to analyze intersubband transition(ISBT)of InGaAs/InAlAs quantum cascade detecto...We demonstrate the use of an infrared modulated photoluminescence(PL)method based on a step-scan Fourier-transform infrared spectrometer to analyze intersubband transition(ISBT)of InGaAs/InAlAs quantum cascade detector(QCD)structures.By configuring oblique and parallel excitation geometries,high signal-to-noise ratio PL spectra in near-to-far-infrared region are measured.With support from numerical calculations based on the k·p perturbation theory,the spectra is attributed to intraband and interband transitions of InGaAs/InAlAs QCD structures.Temperature evolution results show that the k-dependent transitions caused by longitudinal optical phonon-assisted scattering(Frohlich interaction)plays an important role in the ISBT.These results suggest that this infrared modulated-PL method has great potential in characterizing QCD devices and conducting performance diagnostics.展开更多
The external pressure is one of the essential parameters for regulating the structure and energy con-version properties of antiferroelectric AgNbO_(3).For pure AgNbO_(3),however,there has been still a blank of its rea...The external pressure is one of the essential parameters for regulating the structure and energy con-version properties of antiferroelectric AgNbO_(3).For pure AgNbO_(3),however,there has been still a blank of its real lattice structure under the stress field.Here,high-pressure lattice structures and phase transitions of AgNbO_(3)have been explored by spectroscopic experiments and theoretical models.A successive phase transition process from Pbcm to C222_(1) to P2_(1) has been observed at the pressure range of 0-30 GPa,associated with displacive-type characterized by soft-mode kinetics.Note that the paraelectric phase cannot be achieved under high-pressure at room temperature.Significantly,the competition of long-range Coulomb force,short-range interatomic interaction,and covalent interaction in AgNbO_(3)lattice were demonstrated under the stress field.The present work can provide fundamental guidelines to reveal the high-pressure phase transitions of AgNbO_(3),which will open up possibilities for the designing device with functional properties at extremes.展开更多
基金supported by the National Key Research and Development Program of China(Grant No.2019YFB2203400)the National Natural Science Foundation of China(Grant Nos.61974044 and 11974368)the Shanghai Committee of Science and Technology of China(Grant Nos.20142201000 and 21ZR1421500)。
文摘We demonstrate the use of an infrared modulated photoluminescence(PL)method based on a step-scan Fourier-transform infrared spectrometer to analyze intersubband transition(ISBT)of InGaAs/InAlAs quantum cascade detector(QCD)structures.By configuring oblique and parallel excitation geometries,high signal-to-noise ratio PL spectra in near-to-far-infrared region are measured.With support from numerical calculations based on the k·p perturbation theory,the spectra is attributed to intraband and interband transitions of InGaAs/InAlAs QCD structures.Temperature evolution results show that the k-dependent transitions caused by longitudinal optical phonon-assisted scattering(Frohlich interaction)plays an important role in the ISBT.These results suggest that this infrared modulated-PL method has great potential in characterizing QCD devices and conducting performance diagnostics.
基金supported by the National Natural Science Foundation of China(Grant Nos.62090013,61974043,12104156,62074058,61974044)the National Key Research and Development Program of China(Grants No.2019YFB2203403)+1 种基金Projects of Science and Technology Commission of Shanghai Municipality(Grant Nos.21JC1402100 and 23ZR1446400)Natural Science Foundation of Chongqing,China(CSTB2022NSCQ-MSX1367),the Program for Professor of Special Appointment(Eastern Scholar)at Shanghai Institutions of Higher Learning.
文摘The external pressure is one of the essential parameters for regulating the structure and energy con-version properties of antiferroelectric AgNbO_(3).For pure AgNbO_(3),however,there has been still a blank of its real lattice structure under the stress field.Here,high-pressure lattice structures and phase transitions of AgNbO_(3)have been explored by spectroscopic experiments and theoretical models.A successive phase transition process from Pbcm to C222_(1) to P2_(1) has been observed at the pressure range of 0-30 GPa,associated with displacive-type characterized by soft-mode kinetics.Note that the paraelectric phase cannot be achieved under high-pressure at room temperature.Significantly,the competition of long-range Coulomb force,short-range interatomic interaction,and covalent interaction in AgNbO_(3)lattice were demonstrated under the stress field.The present work can provide fundamental guidelines to reveal the high-pressure phase transitions of AgNbO_(3),which will open up possibilities for the designing device with functional properties at extremes.
