We report the preparation of p-type ZnO thin films on （0001） sapphire substrates by a combination of sol-gel and ion-implantation techniques. The results of the Hall-effect measurements carried out at room temperatu...We report the preparation of p-type ZnO thin films on （0001） sapphire substrates by a combination of sol-gel and ion-implantation techniques. The results of the Hall-effect measurements carried out at room temperature indicate that the N-implanted ZnO：Al films annealed at 600℃ have converted to p-type conduction with a hole concentration of 1.6 × 1018 cm^-3, a hole mobility of 3.67cm^2/V· s and a minimum resistivity of 4.80 cm-Ω. Ion-beam induced damage recovery has been investigated by x-ray diffraction （XRD）, photoluminescence （PL） and optical transmittance measurements. Results show that diffraction peaks and PL intensities are decreased by N ion implantation, but they nearly recover after annealing at 600℃. Our results demonstrate a promising approach to fabricate p-type ZnO at a low cost.展开更多
Sr3.96Al14025：Eu2＋,Dy3＋ long persistent materials with different weights of H3BO3 prepared by the high temper- ature solid-state reaction method were characterized by X-ray powder diffraction （XRD）, scanning elec...Sr3.96Al14025：Eu2＋,Dy3＋ long persistent materials with different weights of H3BO3 prepared by the high temper- ature solid-state reaction method were characterized by X-ray powder diffraction （XRD）, scanning electronic microscopy （SEM）, photoluminescence spectra （PL）, and thermoluminescence （TL）. The results of XRD indicate that the 3% addition of H3BO3 favorable for the formation of pure phase Sr4Al14025, and SrAl12O19 was generated when there is a low con- tent or high content of H3BO3. The average grain sizes of samples grow bigger with an increase of H3BO3. PL spectra show that the emission peak does not shift evidently and the emission intensity changes little, indicating that the different amount of H3BO3 has little influence on the crystal field. The decay characteristics and TL measurement show that H3BO3 affects the afterglow properties of Sr3.96Al14025：Eu2＋,Dy3＋, because the increasing H3BO3 leads to more defects in the Sr4Al14025 matrix.展开更多
Doping is an effective approach for improving the photovoltaic performance of Cu2 ZnSnS4（CZTS）. The doping by substitution of Cu atoms in CZTS with Li and Ag atoms is investigated using density functional theory. Th...Doping is an effective approach for improving the photovoltaic performance of Cu2 ZnSnS4（CZTS）. The doping by substitution of Cu atoms in CZTS with Li and Ag atoms is investigated using density functional theory. The results show that the band gaps of Li（2 x）Cu2（1-x）ZnSnS4 and Ag（2 x）Cu2（1-x）ZnSnS4 can be tuned in the ranges of 1.30-3.43 and 1.30-1.63 eV, respectively. The calculation also reveals a phase transition from kesterite to wurtzite-kesterite for Li（2 x）Cu2（1-x）ZnSnS4 as x is larger than 0.9. The tunable band gaps of Li（2 x）Cu2（1-x）ZnSnS4 and Ag（2 x）Cu2（1-x） ZnSnS4 make them beneficial for achieving band-gap-graded solar cells.展开更多
We discuss the surface plasmon-polaritons used for ultrathin metal films with the aid of linear response theory and make comparisons with the known result given by Economou E N. In this paper we consider transverse el...We discuss the surface plasmon-polaritons used for ultrathin metal films with the aid of linear response theory and make comparisons with the known result given by Economou E N. In this paper we consider transverse electromagnetic fields and assume that the electromagnetic field in the linear response formula is the induced field due to the current of the electrons. It satisfies the Maxwell equation and thus we replace the current （charge） term in the Maxwell equation with the linear response expectation value. Finally, taking the external field to be zero, we obtain the dispersion relation of the surface plasmons from the eigenvalue equation. In addition, the charge-density and current-density in the z direction on the surface of ultrathin metal films are also calculated. The results may be helpful to the fundamental understanding of the complex phenomenon of surface plasmon-polaritons.展开更多
Using the linear response theory and random phase approximation, we develop a general dynamic electron transport theory for multiprobe mesoscopic structures in an arbitrarily time-dependent external field. In this cas...Using the linear response theory and random phase approximation, we develop a general dynamic electron transport theory for multiprobe mesoscopic structures in an arbitrarily time-dependent external field. In this case, the responses of the dynamic current, charge and internal potential to the external fields can be determined self-consistently. Without loss of generality, charge （current） conservation and gauge invariance under a potential shift are satisfied. As an example, we employ a quantum wire with a single barrier to discuss the response of the internal potential.展开更多
基金Project supported by the Program for New Century Excellent Talents in University (Grant No NCET-04-0899)Special Foundation for University Subject Construction, Department of Education of Guangdong Province, China (Grant No [2006] 11)
文摘We report the preparation of p-type ZnO thin films on （0001） sapphire substrates by a combination of sol-gel and ion-implantation techniques. The results of the Hall-effect measurements carried out at room temperature indicate that the N-implanted ZnO：Al films annealed at 600℃ have converted to p-type conduction with a hole concentration of 1.6 × 1018 cm^-3, a hole mobility of 3.67cm^2/V· s and a minimum resistivity of 4.80 cm-Ω. Ion-beam induced damage recovery has been investigated by x-ray diffraction （XRD）, photoluminescence （PL） and optical transmittance measurements. Results show that diffraction peaks and PL intensities are decreased by N ion implantation, but they nearly recover after annealing at 600℃. Our results demonstrate a promising approach to fabricate p-type ZnO at a low cost.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 21271048, 11147152, and 61106124)the Natural Science Fund of Zhanjiang Normal University of China (Grant No. QL1020)
文摘Sr3.96Al14025：Eu2＋,Dy3＋ long persistent materials with different weights of H3BO3 prepared by the high temper- ature solid-state reaction method were characterized by X-ray powder diffraction （XRD）, scanning electronic microscopy （SEM）, photoluminescence spectra （PL）, and thermoluminescence （TL）. The results of XRD indicate that the 3% addition of H3BO3 favorable for the formation of pure phase Sr4Al14025, and SrAl12O19 was generated when there is a low con- tent or high content of H3BO3. The average grain sizes of samples grow bigger with an increase of H3BO3. PL spectra show that the emission peak does not shift evidently and the emission intensity changes little, indicating that the different amount of H3BO3 has little influence on the crystal field. The decay characteristics and TL measurement show that H3BO3 affects the afterglow properties of Sr3.96Al14025：Eu2＋,Dy3＋, because the increasing H3BO3 leads to more defects in the Sr4Al14025 matrix.
基金Supported by the National Natural Science Foundation of China under Grant No 61674073the Science and Technology Planning Project of Guangdong Province under Grant No 2017A050506056+1 种基金the Key Basic and Applied Research Project of Guangdong Province under Grant No 2016KZDXM021the Project of International as well as Hongkong,Macao and Taiwan Science and Technology Cooperation Innovation Platform in Universities in Guangdong Province under Grant No 2015KGJHZ028
文摘Doping is an effective approach for improving the photovoltaic performance of Cu2 ZnSnS4（CZTS）. The doping by substitution of Cu atoms in CZTS with Li and Ag atoms is investigated using density functional theory. The results show that the band gaps of Li（2 x）Cu2（1-x）ZnSnS4 and Ag（2 x）Cu2（1-x）ZnSnS4 can be tuned in the ranges of 1.30-3.43 and 1.30-1.63 eV, respectively. The calculation also reveals a phase transition from kesterite to wurtzite-kesterite for Li（2 x）Cu2（1-x）ZnSnS4 as x is larger than 0.9. The tunable band gaps of Li（2 x）Cu2（1-x）ZnSnS4 and Ag（2 x）Cu2（1-x） ZnSnS4 make them beneficial for achieving band-gap-graded solar cells.
基金supported by the Cultivation of Innovative Talents of the Colleges and Universities of Guangdong Province of China(Grant No. LYM10098)
文摘We discuss the surface plasmon-polaritons used for ultrathin metal films with the aid of linear response theory and make comparisons with the known result given by Economou E N. In this paper we consider transverse electromagnetic fields and assume that the electromagnetic field in the linear response formula is the induced field due to the current of the electrons. It satisfies the Maxwell equation and thus we replace the current （charge） term in the Maxwell equation with the linear response expectation value. Finally, taking the external field to be zero, we obtain the dispersion relation of the surface plasmons from the eigenvalue equation. In addition, the charge-density and current-density in the z direction on the surface of ultrathin metal films are also calculated. The results may be helpful to the fundamental understanding of the complex phenomenon of surface plasmon-polaritons.
基金Project supported by the Foundation for Distinguished Young Talents in Higher Education of Guangdong Province of China (Grant No.LYM10098)the Doctor Subject Foundation of Zhanjiang Normal University of China (Grant No.ZL1004)
文摘Using the linear response theory and random phase approximation, we develop a general dynamic electron transport theory for multiprobe mesoscopic structures in an arbitrarily time-dependent external field. In this case, the responses of the dynamic current, charge and internal potential to the external fields can be determined self-consistently. Without loss of generality, charge （current） conservation and gauge invariance under a potential shift are satisfied. As an example, we employ a quantum wire with a single barrier to discuss the response of the internal potential.
