Multiple phase-shifted(MPS)diffraction grating is an effective way proposed to overcome the spatial hole burning(SHB)effect in a distributed feedback(DFB)laser.We present two symmetric λ/8 phase-shifted DFB lasers by...Multiple phase-shifted(MPS)diffraction grating is an effective way proposed to overcome the spatial hole burning(SHB)effect in a distributed feedback(DFB)laser.We present two symmetric λ/8 phase-shifted DFB lasers by using nanoimprint lithography(NIL).The threshold current of a typical laser is less than 15 mA.The side mode suppression ratio(SMSR)is still above 42 dB even at 100 mA current injection.To show the versatility of NIL,eight different wavelength MPS-DFB lasers on this single chip are also demonstrated.Our results prove that NIL is a promising tool for fabricating high performance complex grating DFB lasers.展开更多
A stacked lateral double-diffused metal–oxide–semiconductor field-effect transistor(LDMOS) with enhanced depletion effect by surface substrate is proposed(ST-LDMOS), which is compatible with the traditional CMOS pro...A stacked lateral double-diffused metal–oxide–semiconductor field-effect transistor(LDMOS) with enhanced depletion effect by surface substrate is proposed(ST-LDMOS), which is compatible with the traditional CMOS processes. The new stacked structure is characterized by double substrates and surface dielectric trenches(SDT). The drift region is separated by the P-buried layer to form two vertically parallel devices. The doping concentration of the drift region is increased benefiting from the enhanced auxiliary depletion effect of the double substrates, leading to a lower specific on-resistance(Ron,sp). Multiple electric field peaks appear at the corners of the SDT, which improves the lateral electric field distribution and the breakdown voltage(BV). Compared to a conventional LDMOS(C-LDMOS), the BV in the ST-LDMOS increases from 259 V to 459 V, an improvement of 77.22%. The Ron,sp decreases from 39.62 m?·cm^2 to 23.24 m?·cm^2 and the Baliga's figure of merit(FOM) of is 9.07 MW/cm^2.展开更多
We proposed a sandwich structure to realize broadband asymmetric transmission(AT) for both linearly and circularly polarized waves in the near infrared spectral region. The structure composes of a silica substrate and...We proposed a sandwich structure to realize broadband asymmetric transmission(AT) for both linearly and circularly polarized waves in the near infrared spectral region. The structure composes of a silica substrate and two sand-clock-like gold layers on the opposite sides of the substrate. Due to the surface plasmons of gold, the structure shows that the AT parameters of linearly and circularly polarized waves can reach 0.436 and 0.403, respectively. Meanwhile, a broadband property is presented for the AT parameter is over 0.3 between 320 THz and 340 THz. The structure realizes a diode-like AT for linearly wave in forward and circularly wave in backward, respectively. The magnetic dipoles excited by current in the two gold layers contribute to the broadband AT. The current density in top and bottom metallic layers illustrates the mechanism of the polarization conversion for broadband AT in detail.展开更多
Ferroelectric(FE)HfZrO/Al_(2)O_(3) gate stack AlGaN/GaN metal-FE-semiconductor heterostructure high-electron mo-bility transistors(MFSHEMTs)with varying Al_(x)Ga_(1-x)N barrier thickness and Al composition are investi...Ferroelectric(FE)HfZrO/Al_(2)O_(3) gate stack AlGaN/GaN metal-FE-semiconductor heterostructure high-electron mo-bility transistors(MFSHEMTs)with varying Al_(x)Ga_(1-x)N barrier thickness and Al composition are investigated and com-pared by TCAD simulation with non-FE HfO_(2)/Al_(2)O_(3) gate stack metal-insulator-semiconductor heterostructure high-electron mobility transistors(MISHEMTs).Results show that the decrease of the two-dimensional electron gas(2DEG)density with decreasing AlGaN barrier thickness is more effectively suppressed in MFSHEMTs than that in MISHEMTs due to the enhanced FE polarization switching efficiency.The electrical characteristics of MFSHEMTs,including transcon-ductance,subthreshold swing,and on-state current,effectively improve with decreasing AlGaN thickness in MFSHEMTs.High Al composition in AlGaN barrier layers that are under 3-nm thickness plays a great role in enhancing the 2DEG den-sity and FE polarization in MFSHEMTs,improving the transconductance and the on-state current.The subthreshold swing and threshold voltage can be reduced by decreasing the AlGaN thickness and Al composition in MFSHEMTs,affording favorable conditions for further enhancing the device.展开更多
BaTiO3 （BTO） ferroelectric thin films are prepared by the sol,el method. The fabrication and the optical properties of an InGaN/GaN multiple quantum well light emitting diode （LED） with amorphous BTO ferroelectric...BaTiO3 （BTO） ferroelectric thin films are prepared by the sol,el method. The fabrication and the optical properties of an InGaN/GaN multiple quantum well light emitting diode （LED） with amorphous BTO ferroelectric thin film are studied. The photolumineseence （PL） of the BTO ferroelectric film is attributed to the structure. The ferroeleetric film which annealed at 673 K for 8 h has the better PL property. The peak width is about 30 nm from 580 nm to 610 nm, towards the yellow region. The mixed electroluminescence （EL） spectrum of InGaN/GaN multiple quantum well LED with 150-nm thick amorphous BTO ferroelectric thin film displays the blue-white light. The Commission Internationale De L＇Eclairage （CIE） coordinate of EL is （0.2139, 0.1627）. EL wavelength and intensity depends on the composition, microstructure and thickness of the ferroelectric thin film. The transmittance of amorphous BTO thin film is about 93% at a wavelength of 450 nm-470 nm. This means the amorphous ferroelectrie thin films can output more blue-ray and emission lights. In addition, the amorphous ferroelectric thin films can be directly fabricated without a binder and used at higher temperatures （200 ℃-400 ℃）. It is very favourable to simplify the preparation process and reduce the heat dissipation requirements of an LED. This provides a new way to study LEDs.展开更多
基金the National Natural Science Foundation of China under Grant Nos 11044009,A040507,61076042 and 60607006the Special Project on Development of National Key Scientific Instruments and Equipment of China under Grant No 2011YQ16000205+2 种基金the National Key Technology R&D Program of China under Grant No 2009BAH49B01the National High-Technology Research and Development Program of China under Grant Nos 2011AA010304 and 2011AA03A106the Science and Technology Special Project in Hubei Province under Grant No 2009AAA009.
文摘Multiple phase-shifted(MPS)diffraction grating is an effective way proposed to overcome the spatial hole burning(SHB)effect in a distributed feedback(DFB)laser.We present two symmetric λ/8 phase-shifted DFB lasers by using nanoimprint lithography(NIL).The threshold current of a typical laser is less than 15 mA.The side mode suppression ratio(SMSR)is still above 42 dB even at 100 mA current injection.To show the versatility of NIL,eight different wavelength MPS-DFB lasers on this single chip are also demonstrated.Our results prove that NIL is a promising tool for fabricating high performance complex grating DFB lasers.
基金supported by the National Natural Science Foundation of China(Grant No.61464003)the Guangxi Natural Science Foundation,China(Grant Nos.2015GXNSFAA139300 and 2018JJA170010)
文摘A stacked lateral double-diffused metal–oxide–semiconductor field-effect transistor(LDMOS) with enhanced depletion effect by surface substrate is proposed(ST-LDMOS), which is compatible with the traditional CMOS processes. The new stacked structure is characterized by double substrates and surface dielectric trenches(SDT). The drift region is separated by the P-buried layer to form two vertically parallel devices. The doping concentration of the drift region is increased benefiting from the enhanced auxiliary depletion effect of the double substrates, leading to a lower specific on-resistance(Ron,sp). Multiple electric field peaks appear at the corners of the SDT, which improves the lateral electric field distribution and the breakdown voltage(BV). Compared to a conventional LDMOS(C-LDMOS), the BV in the ST-LDMOS increases from 259 V to 459 V, an improvement of 77.22%. The Ron,sp decreases from 39.62 m?·cm^2 to 23.24 m?·cm^2 and the Baliga's figure of merit(FOM) of is 9.07 MW/cm^2.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11965009,61874036,61805053,and 61764001)the Natural Science Foundation of Guangxi Zhuang Autonomous Region,China(Grant Nos.2018JJA170010 and 2018GXNSFAA281193)the Innovation Project of GUET Graduate Education(Grant No.2020YCXS019)。
文摘We proposed a sandwich structure to realize broadband asymmetric transmission(AT) for both linearly and circularly polarized waves in the near infrared spectral region. The structure composes of a silica substrate and two sand-clock-like gold layers on the opposite sides of the substrate. Due to the surface plasmons of gold, the structure shows that the AT parameters of linearly and circularly polarized waves can reach 0.436 and 0.403, respectively. Meanwhile, a broadband property is presented for the AT parameter is over 0.3 between 320 THz and 340 THz. The structure realizes a diode-like AT for linearly wave in forward and circularly wave in backward, respectively. The magnetic dipoles excited by current in the two gold layers contribute to the broadband AT. The current density in top and bottom metallic layers illustrates the mechanism of the polarization conversion for broadband AT in detail.
基金Project supported by Guangxi Science and Technology Planning Project (Grant Nos. AD19245066, AA19254015, AD21220150, and AD18281037)the National Nature Science Foundation of China (Grant Nos. 61874036, 62174041, and 62041403)+4 种基金China Postdoctoral Science Foundation (Grant No. 2020M683626XB)the Natural Science Foundation of Guangxi Zhuang Autonomous Region (Grant No. 2018GXNSFAA138025)Guangxi Innovation Research Team Project (Grant No. 2018GXNSFGA281004)GUET Excellent Graduate Thesis (Grant No. YXYJRX01)the Fund from the State Key Laboratory of ASIC & System (Grant No. KVH1233021)
文摘Ferroelectric(FE)HfZrO/Al_(2)O_(3) gate stack AlGaN/GaN metal-FE-semiconductor heterostructure high-electron mo-bility transistors(MFSHEMTs)with varying Al_(x)Ga_(1-x)N barrier thickness and Al composition are investigated and com-pared by TCAD simulation with non-FE HfO_(2)/Al_(2)O_(3) gate stack metal-insulator-semiconductor heterostructure high-electron mobility transistors(MISHEMTs).Results show that the decrease of the two-dimensional electron gas(2DEG)density with decreasing AlGaN barrier thickness is more effectively suppressed in MFSHEMTs than that in MISHEMTs due to the enhanced FE polarization switching efficiency.The electrical characteristics of MFSHEMTs,including transcon-ductance,subthreshold swing,and on-state current,effectively improve with decreasing AlGaN thickness in MFSHEMTs.High Al composition in AlGaN barrier layers that are under 3-nm thickness plays a great role in enhancing the 2DEG den-sity and FE polarization in MFSHEMTs,improving the transconductance and the on-state current.The subthreshold swing and threshold voltage can be reduced by decreasing the AlGaN thickness and Al composition in MFSHEMTs,affording favorable conditions for further enhancing the device.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 61076042 and 60607006)the Special Project on Development of National Key Scientific Instruments and Equipment of China (Grant No. 2011YQ16000205)the National High Technology Research and Development Program of China (Grant No. 2011AA03A106)
文摘BaTiO3 （BTO） ferroelectric thin films are prepared by the sol,el method. The fabrication and the optical properties of an InGaN/GaN multiple quantum well light emitting diode （LED） with amorphous BTO ferroelectric thin film are studied. The photolumineseence （PL） of the BTO ferroelectric film is attributed to the structure. The ferroeleetric film which annealed at 673 K for 8 h has the better PL property. The peak width is about 30 nm from 580 nm to 610 nm, towards the yellow region. The mixed electroluminescence （EL） spectrum of InGaN/GaN multiple quantum well LED with 150-nm thick amorphous BTO ferroelectric thin film displays the blue-white light. The Commission Internationale De L＇Eclairage （CIE） coordinate of EL is （0.2139, 0.1627）. EL wavelength and intensity depends on the composition, microstructure and thickness of the ferroelectric thin film. The transmittance of amorphous BTO thin film is about 93% at a wavelength of 450 nm-470 nm. This means the amorphous ferroelectrie thin films can output more blue-ray and emission lights. In addition, the amorphous ferroelectric thin films can be directly fabricated without a binder and used at higher temperatures （200 ℃-400 ℃）. It is very favourable to simplify the preparation process and reduce the heat dissipation requirements of an LED. This provides a new way to study LEDs.
