Ge self-assembled quantum dots （SAQDs） are grown with a self-assembled UHV/CVD epitaxy system. Then, the as-grown Ge quantum dots are annealed by ArF excimer laser. In the ultra-shot laser pulse duration, -20ns, bul...Ge self-assembled quantum dots （SAQDs） are grown with a self-assembled UHV/CVD epitaxy system. Then, the as-grown Ge quantum dots are annealed by ArF excimer laser. In the ultra-shot laser pulse duration, -20ns, bulk diffusion is forbidden,and only surface diffusion occurs, resulting in a laser induced quantum dot （LIQD）. The diameter of the LIQD is 20-25nm which is much smaller than the as-grown dot and the LIQD has a higher density of about 6 ×10^10cm^-2. The surface morphology evolution is investigated by AFM.展开更多
The effect of rapid thermal annealing on the optical properties of astrained InAs/InP single quantum well structrure has been investigated in this paper.The luminescence intensity of the quantum well at 8 K was increa...The effect of rapid thermal annealing on the optical properties of astrained InAs/InP single quantum well structrure has been investigated in this paper.The luminescence intensity of the quantum well at 8 K was increased by a factor of 4 and 1.55 meV blue shift of the quantum well photoluminescence peak was observed after annealing at the optimal condition of 700℃ for 5 s. Furthermore,we found that the luminescence efficiency of the deep radiative levels in the samples was also affected by rapid thermal annealing.Our experimental results have demonstrated that Rapid thermal annealing significantly improves the crystalline quality of strained quantum well structures after growth and is an important way for enhancement of the performance of the laser device.展开更多
Nano-ZnO thin films composed of nanoparticles with sizes of 10-16 nm on silicon substrates at low temperature were prepared by sol-gel method.By placing the nano-ZnO thin films at room temperature or annealing at 100&...Nano-ZnO thin films composed of nanoparticles with sizes of 10-16 nm on silicon substrates at low temperature were prepared by sol-gel method.By placing the nano-ZnO thin films at room temperature or annealing at 100°C in air for 10 h intermittently,within a total 70 h annealing time,the evolution of PL spectra of the nano-ZnO thin films were studied in detail.As the annealing time increases,the PL peaks shift from violet to blue and green bands.The PL peaks at violet and blue bands decrease with the annealing time,but the PL peaks at green band are opposite.The PL spectra are related to the defects in the nano-ZnO thin films.The PL peaks positioned at 430 nm are mainly related to defects of zinc interstatials(Zni),oxygen vacancies and(Vo);the ones at 420 nm to oxygen interstitials(Oi),Zinc vacancies(Vzn),Zni ;and the ones at 468 nm to Vzn,Zni,and charged oxygen interstatials(Vo+).The green luminescence is related to Oi,Vo and Zni.The evolutions of PL spectra and the defects are also related to the concentrations of Zn in the thin films,the thicknesses of the films and the annealing time.For the films with 0.5 M and 1.0 M Zn concentrations,after 20 h and 30 h annealing in air at 100°C,respectively,either placing them in air at room temperature or continuing anneal in air at 100°C,the PL spectra are stable.Under the low temperature annealing,Zni decreases with the annealing time,and Oi increases.Sufficient Oi favors to keep the nano-ZnO thin films stable.This result is important to nano-ZnO thin films as electron transport layers in inverted or tandem organic solar cells.展开更多
In the present work, the photoluminescence （PL） character of single crystal sapphire （A1203） samples with and without im- plantation by 110 keV He and/or irradiation by 230-MeV Pb ions, as well as subsequently ann...In the present work, the photoluminescence （PL） character of single crystal sapphire （A1203） samples with and without im- plantation by 110 keV He and/or irradiation by 230-MeV Pb ions, as well as subsequently annealing at 600, 900 and 1100 K （TA） was studied. The modification of the structure and optical properties induced by ion irradiation were analyzed by using PL and FTIR spectra. The PL measurements showed that luminescence peaks located at 390, 413,450, and 564 nm appeared in irradiated samples. The luminescence peaks appeared at 360, 380, and 516 nm after annealing. Infrared spectra showed a broad- ening of the absorption band between 460 cm^-1 and 510 cm^-1, which indicated the formation of strongly damaged regions in the Al2O3 samples. The position shift of the absorption band in 1000-1300 cm^-1 tended towards to a higher wavelength.展开更多
文摘Ge self-assembled quantum dots （SAQDs） are grown with a self-assembled UHV/CVD epitaxy system. Then, the as-grown Ge quantum dots are annealed by ArF excimer laser. In the ultra-shot laser pulse duration, -20ns, bulk diffusion is forbidden,and only surface diffusion occurs, resulting in a laser induced quantum dot （LIQD）. The diameter of the LIQD is 20-25nm which is much smaller than the as-grown dot and the LIQD has a higher density of about 6 ×10^10cm^-2. The surface morphology evolution is investigated by AFM.
文摘The effect of rapid thermal annealing on the optical properties of astrained InAs/InP single quantum well structrure has been investigated in this paper.The luminescence intensity of the quantum well at 8 K was increased by a factor of 4 and 1.55 meV blue shift of the quantum well photoluminescence peak was observed after annealing at the optimal condition of 700℃ for 5 s. Furthermore,we found that the luminescence efficiency of the deep radiative levels in the samples was also affected by rapid thermal annealing.Our experimental results have demonstrated that Rapid thermal annealing significantly improves the crystalline quality of strained quantum well structures after growth and is an important way for enhancement of the performance of the laser device.
基金supported by the National Natural Science Foundation of China (Grant Nos. 41172110,61107090)Shandong Provincial Natural Science Foundation (Grant No. ZR2011BZ007)
文摘Nano-ZnO thin films composed of nanoparticles with sizes of 10-16 nm on silicon substrates at low temperature were prepared by sol-gel method.By placing the nano-ZnO thin films at room temperature or annealing at 100°C in air for 10 h intermittently,within a total 70 h annealing time,the evolution of PL spectra of the nano-ZnO thin films were studied in detail.As the annealing time increases,the PL peaks shift from violet to blue and green bands.The PL peaks at violet and blue bands decrease with the annealing time,but the PL peaks at green band are opposite.The PL spectra are related to the defects in the nano-ZnO thin films.The PL peaks positioned at 430 nm are mainly related to defects of zinc interstatials(Zni),oxygen vacancies and(Vo);the ones at 420 nm to oxygen interstitials(Oi),Zinc vacancies(Vzn),Zni ;and the ones at 468 nm to Vzn,Zni,and charged oxygen interstatials(Vo+).The green luminescence is related to Oi,Vo and Zni.The evolutions of PL spectra and the defects are also related to the concentrations of Zn in the thin films,the thicknesses of the films and the annealing time.For the films with 0.5 M and 1.0 M Zn concentrations,after 20 h and 30 h annealing in air at 100°C,respectively,either placing them in air at room temperature or continuing anneal in air at 100°C,the PL spectra are stable.Under the low temperature annealing,Zni decreases with the annealing time,and Oi increases.Sufficient Oi favors to keep the nano-ZnO thin films stable.This result is important to nano-ZnO thin films as electron transport layers in inverted or tandem organic solar cells.
基金supported by the National Natural Science Foundation of China (Grant Nos. 10705037 and 10975165)
文摘In the present work, the photoluminescence （PL） character of single crystal sapphire （A1203） samples with and without im- plantation by 110 keV He and/or irradiation by 230-MeV Pb ions, as well as subsequently annealing at 600, 900 and 1100 K （TA） was studied. The modification of the structure and optical properties induced by ion irradiation were analyzed by using PL and FTIR spectra. The PL measurements showed that luminescence peaks located at 390, 413,450, and 564 nm appeared in irradiated samples. The luminescence peaks appeared at 360, 380, and 516 nm after annealing. Infrared spectra showed a broad- ening of the absorption band between 460 cm^-1 and 510 cm^-1, which indicated the formation of strongly damaged regions in the Al2O3 samples. The position shift of the absorption band in 1000-1300 cm^-1 tended towards to a higher wavelength.
