We report a type-ⅡGaSb-based interband cascade laser operating a continuous wave at room temperature.The cascade region of interband cascade laser was designed using the‘W'configuration of the active quantum wel...We report a type-ⅡGaSb-based interband cascade laser operating a continuous wave at room temperature.The cascade region of interband cascade laser was designed using the‘W'configuration of the active quantum wells and the‘Carrier Rebalancing'method in the electron injector.The devices were processed into narrow ridges and mounted epitaxial side down on a copper heat sink.The 25-μm-wide,3-mm-long ridge without coated facets generated 41.4 mW of continuous wave output power at T=15℃.And a low threshold current density of 267 A/cm^2 is achieved.The emission wavelength of the ICL is 3452.3 nm at 0.5 A.展开更多
Here in this paper,we report a room-temperature operating infrared photodetector based on the interband transition of an In As Sb/Ga Sb quantum well.The interband transition energy of 5-nm thick In As（0.91）Sb（0.09...Here in this paper,we report a room-temperature operating infrared photodetector based on the interband transition of an In As Sb/Ga Sb quantum well.The interband transition energy of 5-nm thick In As（0.91）Sb（0.09） embedded in the Ga Sb barrier is calculated to be 0.53 e V（2.35μm）,which makes the absorption range of In As Sb cover an entire range from short-wavelength infrared to long-wavelength infrared spectrum.The fabricated photodetector exhibits a narrow response range from 2.0μm to 2.3μm with a peak around 2.1μm at 300 K.The peak responsivity is 0.4 A/W under-500-m Vapplied bias voltage,corresponding to a peak quantum efficiency of 23.8%in the case without any anti-reflection coating.At 300 K,the photodetector exhibits a dark current density of 6.05×10^-3A/cm^2 under-400-m V applied bias voltage and 3.25×10^-5A/cm^2 under zero,separately.The peak detectivity is 6.91×10^10cm·Hz^1/2/W under zero bias voltage at 300 K.展开更多
Compared with the widespread exploitation of hot electrons in plasmonic nanoparticles(NPs),hot holes generated from plasmonic metal interband transitions,are often overlooked in photoelectrochemistry,including photoel...Compared with the widespread exploitation of hot electrons in plasmonic nanoparticles(NPs),hot holes generated from plasmonic metal interband transitions,are often overlooked in photoelectrochemistry,including photoelectrochemical sensing.Motivated by the subtle spectral overlap between the characteristic plasmonic bands of Ag NPs and interband transitions of Au,herein,we construct unusual core-shell Ag@Au NPs via an anti-galvanic reaction to promote the generation of hot holes.Benefiting from the unique plasmon resonances of Ag cores in specific wavelength regimes,Ag@Au can excite multiplied hot holes while Au cannot under the same conditions.With satisfactory accuracy and good practicability,the photoelectrochemical sensing platform based on Ag@Au NPs possesses a detection limit of 77 nmol/L for glucose,exhibiting significantly higher sensitivity compared to that using Au NPs.This work exemplifies the applications of interband hot-hole accumulation initiated by plasmons and may inspire more strategies to explore the utilization of hot holes in photoelectrochemistry.展开更多
Tunnelling, acceleration, and collision of electrons are the basic events in the process of high harmonic generation(HHG) in strong-field interaction with atoms.However, the periodic array of atoms in semiconductor st...Tunnelling, acceleration, and collision of electrons are the basic events in the process of high harmonic generation(HHG) in strong-field interaction with atoms.However, the periodic array of atoms in semiconductor structure makes three steps become interatomic coherent process which leads to complicated carrier dynamics and two sources of high harmonic emission: interband polarization and intraband current.The difference of features of high harmonic generation between semiconductors and atoms is strongly linked to the unique presence of intraband motion which manifests itself a nontrivial role in intertwined two dynamics.Here, we review recent experimental and theoretical advances of understanding coupled interband and intraband mechanisms of HHG in semiconductors.Particularly we focus on the influence of intraband motion on the interband excitation, and on the subsequent HHG emission and attosecond pulse generation.展开更多
We present a method to extend the operating wavelength of the interband transition quantum well photodetector from an extended short-wavelength infrared region to a middle-wavelength infrared region. In the modified I...We present a method to extend the operating wavelength of the interband transition quantum well photodetector from an extended short-wavelength infrared region to a middle-wavelength infrared region. In the modified In As Sb quantum well, Ga Sb is replaced with Al Sb/Al Ga Sb, the valence band of the barrier material is lowered, the first restricted energy level is higher than the valence band of the barrier material, the energy band structure forms type-II structure. The photocurrent spectrum manifest that the fabricated photodetector exhibits a response range from 1.9 μm to 3.2 μm with two peaks at 2.18 μm and 3.03 μm at 78 K.展开更多
Localized surface plasmon has been extensively studied and used for the photocatalysis of various chemical reactions.However,the different contributions between plasmon resonance and interband transition in photocatal...Localized surface plasmon has been extensively studied and used for the photocatalysis of various chemical reactions.However,the different contributions between plasmon resonance and interband transition in photocatalysis has not been well understood.Here,we study the photothermal and hot electrons effects for crystal transformation by combining controlled experiments with numerical simulations.By photo-excitation of Na YF4:Eu^(3+)@Au composite structure,it is found that the plasmonic catalysis is much superior to that of interband transition in the experiments,owing to the hot electrons generated by plasmon decay more energetic to facilitate the reaction.We emphasize that the energy level of hot electrons plays an essential role for improving the photocatalytic activity.The results provide guidelines for improving the efficiency of plasmonic catalysis in future experimental design.展开更多
We report on a long wavelength interband cascade photodetector with type Ⅱ InAs/GaSb superlattice absorber.The device is a three-stage interband cascade structure.At 77 K,the 50%cutoff wavelength of the detector is 8...We report on a long wavelength interband cascade photodetector with type Ⅱ InAs/GaSb superlattice absorber.The device is a three-stage interband cascade structure.At 77 K,the 50%cutoff wavelength of the detector is 8.48μm and the peak photoresponse wavelength is 7.78μm.The peak responsivity is 0.93 A/W and the detectivity D*is 1.12×10^(11)cm·Hz0.5/W for 7.78μm at-0.20 V.The detector can operate up to about 260 K.At 260 K,the 50%cutoff wavelength is 11.52μm,the peak responsivity is 0.78 A/W and the D*is 5.02×10^(8)cm·Hz0.5/W for the peak wavelength of 10.39μm at-2.75 V.The dark current of the device is dominated by the diffusion current under both a small bias voltage of-0.2 V and a large one of-2.75 V for the temperature range of 120 to 260 K.展开更多
The influence of the pressure transmission medium（PTM）on the excitonic interband transitions in monolayer tungsten diselenide（WSe2）is investigated using photoluminescence（PL）spectra under hydrostatic pressure up...The influence of the pressure transmission medium（PTM）on the excitonic interband transitions in monolayer tungsten diselenide（WSe2）is investigated using photoluminescence（PL）spectra under hydrostatic pressure up to 5GPa.Three kinds of PTMs,condensed argon（Ar）,1：1 n-pentane and isopentane mixture（PM）,and4：1 methanol and ethanol mixture（MEM,a PTM with polarity）,are used.It is found that when either Ar or PM is used as the PTM,the PL peak of exciton related to the direct K-K interband transition shows a pressure-induced blue-shift at a rate of 32±4 or 32±1 meV/GPa,while it turns to be 50±9meV/GPa when MEM is used as the PTM.The indirect A-K interband transition presents almost no shift with increasing pressure up to approximatel.y 5 GPa when Ar and PM are used as the PTM,while it shows a red-shift at the rate of-17±7meV/GPa by using MEM as the PTM.These results reveal that the optical interband transitions of monolayer WSe2 are very sensitive to the polarity of the PTM.The anomalous pressure coefficient obtained using the polar PTM of MEM is ascribed to the existence of hydrogen-like bonds between hydroxyl in MEM and Se atoms under hydrostatic pressure.展开更多
InAs-based interband cascade lasers（ICLs） with InAs plasmon waveguides or InAs/AlSb superlattice（SL） waveguides were demonstrated at emission wavelengths below 4.1 μm. The threshold current densities of the laser...InAs-based interband cascade lasers（ICLs） with InAs plasmon waveguides or InAs/AlSb superlattice（SL） waveguides were demonstrated at emission wavelengths below 4.1 μm. The threshold current densities of the lasers with SL waveguides were 37 A/cm;at 77 K in continuous wave mode. The operation temperature of these lasers reached room temperature in pulsed mode. Compared with the thick InAs n++ plasmon cladding layer, the InAs/AlSb superlattice cladding layers have greater advantages for ICLs with wavelengths less than 4 μm even in InAs based ICLs because in the short-wavelength region they have a higher confinement factor than InAs plasmon waveguides.展开更多
With the progress of the laser manufacturing technology, trace gas sensors based on tunable interband cascade lasers （ICLs） and quantum cascade lasers （QCLs） have been widely used to detect organic compounds with ...With the progress of the laser manufacturing technology, trace gas sensors based on tunable interband cascade lasers （ICLs） and quantum cascade lasers （QCLs） have been widely used to detect organic compounds with high sensitivity. Compared with overtone and combination bands in the near infrared region, for many species, the intensities of fundamental rotational-vibrational absorption bands in the mid-infrared region are much stronger. In this paper, we demonstrate an ethanol sensor using a room-temperature continuous-wave （CW） tunable ICL laser as a light source to detect ethanol vapor concentration with high sensitivity. Combined with the first harmonic （1 f） normalized second harmonic （2f） wavelength modulation spectroscopy （WMS） technology, the characteristics of the harmonics of the system are analyzed, and the amplitude of the first harmonic decrease with an increased concentration of ethanol has been demonstrated both theoretically and experimentally. As a result, a detection limitation of 28 ppb is achieved.展开更多
Interband cascade(IC)photovoltaic(PV)device structures,consisting of multiple discrete InAs/GaSb superlattice absorbers sandwiched between electron and hole barriers,were grown by molecular beam epitaxy.Details of the...Interband cascade(IC)photovoltaic(PV)device structures,consisting of multiple discrete InAs/GaSb superlattice absorbers sandwiched between electron and hole barriers,were grown by molecular beam epitaxy.Details of the molecular beam epitaxy growth and material characterization of the structures are presented.The discrete absorber architecture enables certain advantages,such as high open-circuit voltage,high collection efficiency,high operating temperature,and smooth integration of cascade stages with different bandgaps.The two-and three-stage ICPV devices presented in this article operate at room temperature with substantial open-circuit voltages at a cutoff wavelength of 5.3 lm(corresponding to a bandgap of 0.23 eV),the longest ever reported for room temperature PV devices.The device characteristics indicate a high level of current matching and demonstrate the advantages of the interband cascade approach in thermophotovoltaic cell design.展开更多
We demonstrate Ga Sb-based interband cascade lasers(ICLs) emitting around 3.65 μm, which exhibit a room-temperature continuous-wave(CW) output power above 100 m W. Cavity-length analysis showed that the laser structu...We demonstrate Ga Sb-based interband cascade lasers(ICLs) emitting around 3.65 μm, which exhibit a room-temperature continuous-wave(CW) output power above 100 m W. Cavity-length analysis showed that the laser structure has a low internal loss of 3 cm^(-1) while maintaining a total internal quantum efficiency greater than one. After 6400 h CW operation at 25°C,the threshold current of the laser increased by 3%, and the output power decreased by 7%, indicating good reliability of the device.展开更多
基金Project supported by the Major Program of the National Natural Science Foundation of China(Grant No.61790580)the National Natural Science Foundation of China(Grant No.61435012)the National Basic Research Program of China(Grant No.2014CB643903)
文摘We report a type-ⅡGaSb-based interband cascade laser operating a continuous wave at room temperature.The cascade region of interband cascade laser was designed using the‘W'configuration of the active quantum wells and the‘Carrier Rebalancing'method in the electron injector.The devices were processed into narrow ridges and mounted epitaxial side down on a copper heat sink.The 25-μm-wide,3-mm-long ridge without coated facets generated 41.4 mW of continuous wave output power at T=15℃.And a low threshold current density of 267 A/cm^2 is achieved.The emission wavelength of the ICL is 3452.3 nm at 0.5 A.
基金Project supported by the National Natural Science Foundation of China(Grant No.11574362)
文摘Here in this paper,we report a room-temperature operating infrared photodetector based on the interband transition of an In As Sb/Ga Sb quantum well.The interband transition energy of 5-nm thick In As（0.91）Sb（0.09） embedded in the Ga Sb barrier is calculated to be 0.53 e V（2.35μm）,which makes the absorption range of In As Sb cover an entire range from short-wavelength infrared to long-wavelength infrared spectrum.The fabricated photodetector exhibits a narrow response range from 2.0μm to 2.3μm with a peak around 2.1μm at 300 K.The peak responsivity is 0.4 A/W under-500-m Vapplied bias voltage,corresponding to a peak quantum efficiency of 23.8%in the case without any anti-reflection coating.At 300 K,the photodetector exhibits a dark current density of 6.05×10^-3A/cm^2 under-400-m V applied bias voltage and 3.25×10^-5A/cm^2 under zero,separately.The peak detectivity is 6.91×10^10cm·Hz^1/2/W under zero bias voltage at 300 K.
基金financially supported by the National Natural Science Foundation of China(Nos.22074038 and 21807032)the Natural Science Foundation of Hunan Province(No.2019J30007),and the Fundamental Research Funds for the Central Universities.
文摘Compared with the widespread exploitation of hot electrons in plasmonic nanoparticles(NPs),hot holes generated from plasmonic metal interband transitions,are often overlooked in photoelectrochemistry,including photoelectrochemical sensing.Motivated by the subtle spectral overlap between the characteristic plasmonic bands of Ag NPs and interband transitions of Au,herein,we construct unusual core-shell Ag@Au NPs via an anti-galvanic reaction to promote the generation of hot holes.Benefiting from the unique plasmon resonances of Ag cores in specific wavelength regimes,Ag@Au can excite multiplied hot holes while Au cannot under the same conditions.With satisfactory accuracy and good practicability,the photoelectrochemical sensing platform based on Ag@Au NPs possesses a detection limit of 77 nmol/L for glucose,exhibiting significantly higher sensitivity compared to that using Au NPs.This work exemplifies the applications of interband hot-hole accumulation initiated by plasmons and may inspire more strategies to explore the utilization of hot holes in photoelectrochemistry.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11674209 and 11774215)the High Level University Projects of Guangdong Province of China(Mathematics,Shantou University)+1 种基金the Open Fund of the State Key Laboratory of High Field Laser Physics(SIOM),Chinasupport of the Department of Education of Guangdong Province,China(Grant No.2018KCXTD011)
文摘Tunnelling, acceleration, and collision of electrons are the basic events in the process of high harmonic generation(HHG) in strong-field interaction with atoms.However, the periodic array of atoms in semiconductor structure makes three steps become interatomic coherent process which leads to complicated carrier dynamics and two sources of high harmonic emission: interband polarization and intraband current.The difference of features of high harmonic generation between semiconductors and atoms is strongly linked to the unique presence of intraband motion which manifests itself a nontrivial role in intertwined two dynamics.Here, we review recent experimental and theoretical advances of understanding coupled interband and intraband mechanisms of HHG in semiconductors.Particularly we focus on the influence of intraband motion on the interband excitation, and on the subsequent HHG emission and attosecond pulse generation.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11574362,61210014,11374340,and 11474205)the Innovative Clean-Energy Research and Application Program of Beijing Municipal Science and Technology Commission of China(Grant No.Z151100003515001)the National Key Technology R&D Program of China(Grant No.2016YFB0400302)。
文摘We present a method to extend the operating wavelength of the interband transition quantum well photodetector from an extended short-wavelength infrared region to a middle-wavelength infrared region. In the modified In As Sb quantum well, Ga Sb is replaced with Al Sb/Al Ga Sb, the valence band of the barrier material is lowered, the first restricted energy level is higher than the valence band of the barrier material, the energy band structure forms type-II structure. The photocurrent spectrum manifest that the fabricated photodetector exhibits a response range from 1.9 μm to 3.2 μm with two peaks at 2.18 μm and 3.03 μm at 78 K.
基金the National Key Research and Development Program of China(Grant No.2020YFA0211300)the National Natural Science Foundation of China(Grant Nos.92050112,12074237,and 12004233)the Fundamental Research Funds for Central Universities,China(Grant Nos.GK202103010and GK202103018)。
文摘Localized surface plasmon has been extensively studied and used for the photocatalysis of various chemical reactions.However,the different contributions between plasmon resonance and interband transition in photocatalysis has not been well understood.Here,we study the photothermal and hot electrons effects for crystal transformation by combining controlled experiments with numerical simulations.By photo-excitation of Na YF4:Eu^(3+)@Au composite structure,it is found that the plasmonic catalysis is much superior to that of interband transition in the experiments,owing to the hot electrons generated by plasmon decay more energetic to facilitate the reaction.We emphasize that the energy level of hot electrons plays an essential role for improving the photocatalytic activity.The results provide guidelines for improving the efficiency of plasmonic catalysis in future experimental design.
基金supported in part by China’s NSF Program 61874103
文摘We report on a long wavelength interband cascade photodetector with type Ⅱ InAs/GaSb superlattice absorber.The device is a three-stage interband cascade structure.At 77 K,the 50%cutoff wavelength of the detector is 8.48μm and the peak photoresponse wavelength is 7.78μm.The peak responsivity is 0.93 A/W and the detectivity D*is 1.12×10^(11)cm·Hz0.5/W for 7.78μm at-0.20 V.The detector can operate up to about 260 K.At 260 K,the 50%cutoff wavelength is 11.52μm,the peak responsivity is 0.78 A/W and the D*is 5.02×10^(8)cm·Hz0.5/W for the peak wavelength of 10.39μm at-2.75 V.The dark current of the device is dominated by the diffusion current under both a small bias voltage of-0.2 V and a large one of-2.75 V for the temperature range of 120 to 260 K.
基金Supported by the National Key Research and Development Program of China under Grant No 2016YFA0301202the National Natural Science Foundation of China under Grant Nos 11474275,61674135 and 91536101+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences under Grant No XDPB0603the China Postdoctoral Science Foundation under Grant No 2017M622400
文摘The influence of the pressure transmission medium（PTM）on the excitonic interband transitions in monolayer tungsten diselenide（WSe2）is investigated using photoluminescence（PL）spectra under hydrostatic pressure up to 5GPa.Three kinds of PTMs,condensed argon（Ar）,1：1 n-pentane and isopentane mixture（PM）,and4：1 methanol and ethanol mixture（MEM,a PTM with polarity）,are used.It is found that when either Ar or PM is used as the PTM,the PL peak of exciton related to the direct K-K interband transition shows a pressure-induced blue-shift at a rate of 32±4 or 32±1 meV/GPa,while it turns to be 50±9meV/GPa when MEM is used as the PTM.The indirect A-K interband transition presents almost no shift with increasing pressure up to approximatel.y 5 GPa when Ar and PM are used as the PTM,while it shows a red-shift at the rate of-17±7meV/GPa by using MEM as the PTM.These results reveal that the optical interband transitions of monolayer WSe2 are very sensitive to the polarity of the PTM.The anomalous pressure coefficient obtained using the polar PTM of MEM is ascribed to the existence of hydrogen-like bonds between hydroxyl in MEM and Se atoms under hydrostatic pressure.
基金Project supported by the National Natural Science Foundation of China(Nos.61790583,61774150,61774151)the National Basic Research Program of China(No.2014CB643903)
文摘InAs-based interband cascade lasers（ICLs） with InAs plasmon waveguides or InAs/AlSb superlattice（SL） waveguides were demonstrated at emission wavelengths below 4.1 μm. The threshold current densities of the lasers with SL waveguides were 37 A/cm;at 77 K in continuous wave mode. The operation temperature of these lasers reached room temperature in pulsed mode. Compared with the thick InAs n++ plasmon cladding layer, the InAs/AlSb superlattice cladding layers have greater advantages for ICLs with wavelengths less than 4 μm even in InAs based ICLs because in the short-wavelength region they have a higher confinement factor than InAs plasmon waveguides.
文摘With the progress of the laser manufacturing technology, trace gas sensors based on tunable interband cascade lasers （ICLs） and quantum cascade lasers （QCLs） have been widely used to detect organic compounds with high sensitivity. Compared with overtone and combination bands in the near infrared region, for many species, the intensities of fundamental rotational-vibrational absorption bands in the mid-infrared region are much stronger. In this paper, we demonstrate an ethanol sensor using a room-temperature continuous-wave （CW） tunable ICL laser as a light source to detect ethanol vapor concentration with high sensitivity. Combined with the first harmonic （1 f） normalized second harmonic （2f） wavelength modulation spectroscopy （WMS） technology, the characteristics of the harmonics of the system are analyzed, and the amplitude of the first harmonic decrease with an increased concentration of ethanol has been demonstrated both theoretically and experimentally. As a result, a detection limitation of 28 ppb is achieved.
基金supported in part by the DoE EPSCoR program(DESC0004523)C-SPIN,the Oklahoma/Arkansas MRSEC(DMR0520550)
文摘Interband cascade(IC)photovoltaic(PV)device structures,consisting of multiple discrete InAs/GaSb superlattice absorbers sandwiched between electron and hole barriers,were grown by molecular beam epitaxy.Details of the molecular beam epitaxy growth and material characterization of the structures are presented.The discrete absorber architecture enables certain advantages,such as high open-circuit voltage,high collection efficiency,high operating temperature,and smooth integration of cascade stages with different bandgaps.The two-and three-stage ICPV devices presented in this article operate at room temperature with substantial open-circuit voltages at a cutoff wavelength of 5.3 lm(corresponding to a bandgap of 0.23 eV),the longest ever reported for room temperature PV devices.The device characteristics indicate a high level of current matching and demonstrate the advantages of the interband cascade approach in thermophotovoltaic cell design.
基金This work was supported by the National Key Research and Development Project(No.2018YFB2200500)the National Natural Science Foundation of China(Nos.61790583 and 61774150)。
文摘We demonstrate Ga Sb-based interband cascade lasers(ICLs) emitting around 3.65 μm, which exhibit a room-temperature continuous-wave(CW) output power above 100 m W. Cavity-length analysis showed that the laser structure has a low internal loss of 3 cm^(-1) while maintaining a total internal quantum efficiency greater than one. After 6400 h CW operation at 25°C,the threshold current of the laser increased by 3%, and the output power decreased by 7%, indicating good reliability of the device.
