The effect of back-diffusion of Mg dopants on optoelectronic characteristics of InGaN-based green light-emitting diodes （LEDs） is investigated. The LEDs with less Mg back-diffusion show blue shifts of longer wavelen...The effect of back-diffusion of Mg dopants on optoelectronic characteristics of InGaN-based green light-emitting diodes （LEDs） is investigated. The LEDs with less Mg back-diffusion show blue shifts of longer wavelengths and larger wavelengths with the increasing current, which results from the Mg-dopant-related polarization screening. The LEDs show enhanced efficiency with the decreasing Mg back-diffusion in the lower current region. Light outputs follow the power law L α I^m, with smaller parameter m in the LEDs with less Mg back-diffusion, indicating a lower density of trap states. The trap-assisted tunneling current is also suppressed by reducing Mg- defect-related nonradiative centers in the active region. Furthermore, the forward current-voltage characteristics are improved.展开更多
Relaxor-type ferroelectric perovskites attract a lot of attentions due to their excellent dielectric and electrostrictive properties. (Ba,La)(Mg, Nb)O3(BLMN) ceramics were synthesized from oxides by sintering in airs ...Relaxor-type ferroelectric perovskites attract a lot of attentions due to their excellent dielectric and electrostrictive properties. (Ba,La)(Mg, Nb)O3(BLMN) ceramics were synthesized from oxides by sintering in airs using a conventional mixed oxide process. Thermogravimetry-differential analyzer (TG-DTA) analysis shows that the fired temperature of the Ba(Mg1/3, Nb2/3)O3 is above 1627.2 K. From the study of X-ray diffraction (XRD) patterns, it is founded that the amount of the perovskite phase increases with the increasing amount of La2O3. Furthermore, by the X-ray photoelectron spectroscopy (XPS) analysis, it is discovered that the amount of Nb4+ is increased as La2O3 dopant increases from 0 to 0.04.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 61505197 and 61334009the National High-Technology Research and Development Program of China under Grant No 2014AA032604
文摘The effect of back-diffusion of Mg dopants on optoelectronic characteristics of InGaN-based green light-emitting diodes （LEDs） is investigated. The LEDs with less Mg back-diffusion show blue shifts of longer wavelengths and larger wavelengths with the increasing current, which results from the Mg-dopant-related polarization screening. The LEDs show enhanced efficiency with the decreasing Mg back-diffusion in the lower current region. Light outputs follow the power law L α I^m, with smaller parameter m in the LEDs with less Mg back-diffusion, indicating a lower density of trap states. The trap-assisted tunneling current is also suppressed by reducing Mg- defect-related nonradiative centers in the active region. Furthermore, the forward current-voltage characteristics are improved.
文摘Relaxor-type ferroelectric perovskites attract a lot of attentions due to their excellent dielectric and electrostrictive properties. (Ba,La)(Mg, Nb)O3(BLMN) ceramics were synthesized from oxides by sintering in airs using a conventional mixed oxide process. Thermogravimetry-differential analyzer (TG-DTA) analysis shows that the fired temperature of the Ba(Mg1/3, Nb2/3)O3 is above 1627.2 K. From the study of X-ray diffraction (XRD) patterns, it is founded that the amount of the perovskite phase increases with the increasing amount of La2O3. Furthermore, by the X-ray photoelectron spectroscopy (XPS) analysis, it is discovered that the amount of Nb4+ is increased as La2O3 dopant increases from 0 to 0.04.
