The Al 0.24Ga 0.76As/In 0.22Ga 0.78As single delta-doped PHEMT (SH-PHEMT) and double delta-doped PHEMT (DH-PHEMT) are fabricated and investigated.Based on the employment of double heterojunction,double del...The Al 0.24Ga 0.76As/In 0.22Ga 0.78As single delta-doped PHEMT (SH-PHEMT) and double delta-doped PHEMT (DH-PHEMT) are fabricated and investigated.Based on the employment of double heterojunction,double delta doped design,the DH-PHEMT can enhance the carrier confinement,increase the electron gas density,and improve the electron gas distribution,which is beneficial to the device performance.A high device linearity,high transconductance over a large gate voltage swing,high current drivability are found in DH-PHEMT.These improvements suggest that DH-PHEMT is more suitable for high linearity applications in microwave power device.展开更多
In this paper, we theoretically study the effects of doping concentration ND and an external electric field on the intersubband transitions in InxAl（l-x）N/InyGa（l-y）N single quantum well by solving the Schrodinger...In this paper, we theoretically study the effects of doping concentration ND and an external electric field on the intersubband transitions in InxAl（l-x）N/InyGa（l-y）N single quantum well by solving the Schrodinger and Poisson equations self-consistently. Obtained results including transition energies, the band structure, and the optical absorption have been discussed. The lowest three intersubband transitions （E2 -El）, （E3 -El）, and （E3 -E2） are calculated as functions of doping concentration ND. By increasing the doping concentration ND, the depletion effect can be reduced, and the ionized electrons will compensate the internal electric field which results from the spontaneous polarization. Our results show that an optimum concentration ND exists for which the transition 0.8 eV （1.55 μm） is carried out. Finally, the dependence of the optical absorption α13（ω） on the external electric field and doping concentration is studied. The maximum of the optical absorption can be red-shifted or blue-shifted through varying the doping concentration and the external electric field. The obtained results can be used for designing optical fiber telecommunications operating at 1.55 μm.展开更多
Transparent conducting oxides are increasingly important for optoelectronic and thin film transistor applications.La doped BaSnO_(3)is a strong candidate for its high transparency,high carrier concentration,high mobil...Transparent conducting oxides are increasingly important for optoelectronic and thin film transistor applications.La doped BaSnO_(3)is a strong candidate for its high transparency,high carrier concentration,high mobility and abundancy.However,due to the lack of lattice-matched substrates,the mobility of La:BaSnO_(3)remains inferior to single crystals.Here,by constructing a novel approach via delta doping La:BaSnO_(3)in a BaSnO_(3)/La:BaSnO_(3)/BaSnO_(3)(BSO/LBSO/BSO)heterostructure,we achieved room temperature mobility enhancement up to 110 cm^(2)·V^(−1)·s^(−1)while keeping the high carrier concentration at 5×10^(20)cm^(−3),reaching to the highest electrical conductivity in BaSnO_(3)based systems.The mobility is enhanced more than 100%compared to our La:BaSnO_(3)films,which is among the highest mobility in BaSnO_(3)based films and heterostructures.From atomic structural investigations,we found that both(1)the carrier confinement due to delta doping and(2)dislocation-free La:BaSnO_(3)conducting channel,revealed by atomic resolution scanning transmission electron microscopy(STEM)studies,are responsible for mobility enhancement.The enhanced mobility from heterostructure approach is widely applicable for transparent electrodes and high current thin film transistor applications.展开更多
文摘The Al 0.24Ga 0.76As/In 0.22Ga 0.78As single delta-doped PHEMT (SH-PHEMT) and double delta-doped PHEMT (DH-PHEMT) are fabricated and investigated.Based on the employment of double heterojunction,double delta doped design,the DH-PHEMT can enhance the carrier confinement,increase the electron gas density,and improve the electron gas distribution,which is beneficial to the device performance.A high device linearity,high transconductance over a large gate voltage swing,high current drivability are found in DH-PHEMT.These improvements suggest that DH-PHEMT is more suitable for high linearity applications in microwave power device.
文摘In this paper, we theoretically study the effects of doping concentration ND and an external electric field on the intersubband transitions in InxAl（l-x）N/InyGa（l-y）N single quantum well by solving the Schrodinger and Poisson equations self-consistently. Obtained results including transition energies, the band structure, and the optical absorption have been discussed. The lowest three intersubband transitions （E2 -El）, （E3 -El）, and （E3 -E2） are calculated as functions of doping concentration ND. By increasing the doping concentration ND, the depletion effect can be reduced, and the ionized electrons will compensate the internal electric field which results from the spontaneous polarization. Our results show that an optimum concentration ND exists for which the transition 0.8 eV （1.55 μm） is carried out. Finally, the dependence of the optical absorption α13（ω） on the external electric field and doping concentration is studied. The maximum of the optical absorption can be red-shifted or blue-shifted through varying the doping concentration and the external electric field. The obtained results can be used for designing optical fiber telecommunications operating at 1.55 μm.
基金supported by National Natural Science Foundation of China(Grant Nos.52172115)Nature Science Foundation of Guangdong Province,China(Grant Nos.2022A1515010762)+3 种基金supported by Shenzhen Science and Technology Program(Grant Nos.20231121093057002)Outstanding Talents Training Fund in Shenzhen(202106)supported by the Guangdong Provincial Key Laboratory Program(Grant No.2021B1212040001)Guangdong Basic and Applied Basic Research Foundation(Grant No.2023B1515130003)。
文摘Transparent conducting oxides are increasingly important for optoelectronic and thin film transistor applications.La doped BaSnO_(3)is a strong candidate for its high transparency,high carrier concentration,high mobility and abundancy.However,due to the lack of lattice-matched substrates,the mobility of La:BaSnO_(3)remains inferior to single crystals.Here,by constructing a novel approach via delta doping La:BaSnO_(3)in a BaSnO_(3)/La:BaSnO_(3)/BaSnO_(3)(BSO/LBSO/BSO)heterostructure,we achieved room temperature mobility enhancement up to 110 cm^(2)·V^(−1)·s^(−1)while keeping the high carrier concentration at 5×10^(20)cm^(−3),reaching to the highest electrical conductivity in BaSnO_(3)based systems.The mobility is enhanced more than 100%compared to our La:BaSnO_(3)films,which is among the highest mobility in BaSnO_(3)based films and heterostructures.From atomic structural investigations,we found that both(1)the carrier confinement due to delta doping and(2)dislocation-free La:BaSnO_(3)conducting channel,revealed by atomic resolution scanning transmission electron microscopy(STEM)studies,are responsible for mobility enhancement.The enhanced mobility from heterostructure approach is widely applicable for transparent electrodes and high current thin film transistor applications.
