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
The effect of periodic delta-doping and modulation-doping on high Al content n-AlxGa1-xN (x = 0.55) epilayers grown by MOCVD has been investigated. Measured by XRD, AFM, contactless sheet resistance, and Hall-effect...The effect of periodic delta-doping and modulation-doping on high Al content n-AlxGa1-xN (x = 0.55) epilayers grown by MOCVD has been investigated. Measured by XRD, AFM, contactless sheet resistance, and Hall-effect tests, 8-doped and modulation-doped n-Alx Ga1-xN have better crystal quality, surface morphology and electrical properties as compared with uniformly-doped n-AlxGa1-xN. These improvements are attributed to the SiNx growth mask induced by δ-doping layers and the dislocation-blocking effect induced by both growth techniques. In addition, due to the broadened doping profile ascribed to enhanced dopant diffusion at high growth temperatures (1150 ℃) ofn-Al0.55 Ga0.45N, modulation-doped n-Al0.55 Ga0.45N has similar properties as 8-doped n-Al0.55 Ga0.45N.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.
基金supported by the National High Technology Research and Development Program of China(No.2011AA03 A 111)the National Natural Science Foundation of China(No.61006038)
文摘The effect of periodic delta-doping and modulation-doping on high Al content n-AlxGa1-xN (x = 0.55) epilayers grown by MOCVD has been investigated. Measured by XRD, AFM, contactless sheet resistance, and Hall-effect tests, 8-doped and modulation-doped n-Alx Ga1-xN have better crystal quality, surface morphology and electrical properties as compared with uniformly-doped n-AlxGa1-xN. These improvements are attributed to the SiNx growth mask induced by δ-doping layers and the dislocation-blocking effect induced by both growth techniques. In addition, due to the broadened doping profile ascribed to enhanced dopant diffusion at high growth temperatures (1150 ℃) ofn-Al0.55 Ga0.45N, modulation-doped n-Al0.55 Ga0.45N has similar properties as 8-doped n-Al0.55 Ga0.45N.