In this paper, the interface states of the AlGaN/GaN metal–insulator–semiconductor(MIS) high electron mobility transistors(HEMTs) with an Al2 O3 gate dielectric are systematically evaluated. By frequency-dependent c...In this paper, the interface states of the AlGaN/GaN metal–insulator–semiconductor(MIS) high electron mobility transistors(HEMTs) with an Al2 O3 gate dielectric are systematically evaluated. By frequency-dependent capacitance and conductance measurements, trap density and time constant at Al2 O3/AlGaN and AlGaN/GaN interface are determined.The experimental results reveal that the density of trap states and the activation energy at the Al2 O3/AlGaN interface are much higher than at the AlGaN/GaN interface. The photo-assisted capacitance-voltage measurements are performed to characterize the deep-level traps located near mid-gap at the Al2 O3/AlGaN interface, which indicates that a density of deep-level traps is lower than the density of the shallow-level states.展开更多
利用常规探空、地面观测站、自动站及各家数值预报等资料,对发生在2020年8月下半旬的2次区域性大到暴雨天气过程进行了分析。分析表明,2次过程均是在有较明显的高空槽与高空冷空气配合下的混合性降水;其共同的影响系统为500 h Pa高空槽...利用常规探空、地面观测站、自动站及各家数值预报等资料,对发生在2020年8月下半旬的2次区域性大到暴雨天气过程进行了分析。分析表明,2次过程均是在有较明显的高空槽与高空冷空气配合下的混合性降水;其共同的影响系统为500 h Pa高空槽、700 h Pa切变线、低空急流与地面冷锋;不同点是2次过程中副高与大陆高压脊的强度不同,决定了该次过程的低层系统的位置和走向,进而决定了降水落区差异。过程2中,地面有较清楚的锢囚形势出现,但模式检验表明,各模式对锢囚锋的模拟能力有限;可以利用V-3θ图更好地分析对流性降水的发生潜势。展开更多
基金Project supported by the Key Program of National Natural Science Foundation of China(Grant Nos.61334002 and 61634005)the National Natural Science Foundation of China(Grant Nos.61604114 and 61704124)
文摘In this paper, the interface states of the AlGaN/GaN metal–insulator–semiconductor(MIS) high electron mobility transistors(HEMTs) with an Al2 O3 gate dielectric are systematically evaluated. By frequency-dependent capacitance and conductance measurements, trap density and time constant at Al2 O3/AlGaN and AlGaN/GaN interface are determined.The experimental results reveal that the density of trap states and the activation energy at the Al2 O3/AlGaN interface are much higher than at the AlGaN/GaN interface. The photo-assisted capacitance-voltage measurements are performed to characterize the deep-level traps located near mid-gap at the Al2 O3/AlGaN interface, which indicates that a density of deep-level traps is lower than the density of the shallow-level states.
文摘利用常规探空、地面观测站、自动站及各家数值预报等资料,对发生在2020年8月下半旬的2次区域性大到暴雨天气过程进行了分析。分析表明,2次过程均是在有较明显的高空槽与高空冷空气配合下的混合性降水;其共同的影响系统为500 h Pa高空槽、700 h Pa切变线、低空急流与地面冷锋;不同点是2次过程中副高与大陆高压脊的强度不同,决定了该次过程的低层系统的位置和走向,进而决定了降水落区差异。过程2中,地面有较清楚的锢囚形势出现,但模式检验表明,各模式对锢囚锋的模拟能力有限;可以利用V-3θ图更好地分析对流性降水的发生潜势。
