We investigate the influence of interface charge on electrical performance of NbAIO/A1GaN/GaN metal-oxide- semiconductor high electron mobility transistors （MOSHEMTs）. Through C-V measurements and simulations, we fi...We investigate the influence of interface charge on electrical performance of NbAIO/A1GaN/GaN metal-oxide- semiconductor high electron mobility transistors （MOSHEMTs）. Through C-V measurements and simulations, we find that the donor-type interface fixed charge density Qit of 2.2 × 10^13 cm^-2 exists at the NbA10/A1GaN interface, which induces the shift of the threshold voltage much more negative. Furthermore, a trap density of approximately 0.43 × 10^13-1.14 ×10^13 cm^-2 eV^-1 is obtained at the NaA10/AlGaN interface, which is consistent with the frequency-dependent capacitance and conductance measurement results.展开更多
A series of Ln^3＋（Ln^3＋= Er^3＋/Dy^3＋） ions doped Na2 NbAlO5（NNAO） phosphors were synthesized by solidstate method. The Er^3＋ and Dy^3＋ ions doped phosphors were characterized by XRD, photoluminescence（PL） ...A series of Ln^3＋（Ln^3＋= Er^3＋/Dy^3＋） ions doped Na2 NbAlO5（NNAO） phosphors were synthesized by solidstate method. The Er^3＋ and Dy^3＋ ions doped phosphors were characterized by XRD, photoluminescence（PL） and decay profiles. The Ln^3＋-doped samples are consistent with the pure NNAO phase which is analyzed by the X-ray diffraction result. The PL graphs show that the intensity of luminescence increases with the increasing doping concentrations up to their critical certain values and then decreases at higher concentrations due to the concentration quenching effect of Er^3＋/Dy^3＋ ions. The energy level diagrams containing the positions of 4 f and 5 d energy levels of Er^3＋ and Dy^3＋ ions have been established and studied. In addition, under the ultraviolet light, the prepared NNAO：xLn^3＋（Ln^3＋=Er^3＋/Dy^3＋） phosphors show the characteristic green（Er^3＋）, cyan（Dy^3＋） emission, respectively. Under the excitation of 365 nm,the quantum efficiencies of NNAO：0.01 Er^3＋ and NNAO：0.03 Dy^3＋ phosphors are measured to be 61.7% and72.2%, respectively. The obtained results indicate that the new NNAO：xLn^3＋（Ln^3＋=Er^3＋/Dy^3＋） phosphors are promising applications in white-light emitting diodes field.展开更多
基金Supported by the Basic Science Research Fund for the Central Universities of China under Grant No JB141104
文摘We investigate the influence of interface charge on electrical performance of NbAIO/A1GaN/GaN metal-oxide- semiconductor high electron mobility transistors （MOSHEMTs）. Through C-V measurements and simulations, we find that the donor-type interface fixed charge density Qit of 2.2 × 10^13 cm^-2 exists at the NbA10/A1GaN interface, which induces the shift of the threshold voltage much more negative. Furthermore, a trap density of approximately 0.43 × 10^13-1.14 ×10^13 cm^-2 eV^-1 is obtained at the NaA10/AlGaN interface, which is consistent with the frequency-dependent capacitance and conductance measurement results.
基金Project supported by the Science and Technology Special Development in Guangdong Province of China(2016A010103029)the Science and Technology Project of Guangzhou of China(201607010179)
文摘A series of Ln^3＋（Ln^3＋= Er^3＋/Dy^3＋） ions doped Na2 NbAlO5（NNAO） phosphors were synthesized by solidstate method. The Er^3＋ and Dy^3＋ ions doped phosphors were characterized by XRD, photoluminescence（PL） and decay profiles. The Ln^3＋-doped samples are consistent with the pure NNAO phase which is analyzed by the X-ray diffraction result. The PL graphs show that the intensity of luminescence increases with the increasing doping concentrations up to their critical certain values and then decreases at higher concentrations due to the concentration quenching effect of Er^3＋/Dy^3＋ ions. The energy level diagrams containing the positions of 4 f and 5 d energy levels of Er^3＋ and Dy^3＋ ions have been established and studied. In addition, under the ultraviolet light, the prepared NNAO：xLn^3＋（Ln^3＋=Er^3＋/Dy^3＋） phosphors show the characteristic green（Er^3＋）, cyan（Dy^3＋） emission, respectively. Under the excitation of 365 nm,the quantum efficiencies of NNAO：0.01 Er^3＋ and NNAO：0.03 Dy^3＋ phosphors are measured to be 61.7% and72.2%, respectively. The obtained results indicate that the new NNAO：xLn^3＋（Ln^3＋=Er^3＋/Dy^3＋） phosphors are promising applications in white-light emitting diodes field.
