Improvement of UV electroluminescence of n-ZnO/p-GaN heterojunction LED by ZnS interlayer.
n-ZnO/p-GaN heterojunction light emitting diodes with different interfacial layers were fabricated by pulsed laser deposition. The electroluminescence (EL) spectra of the n-ZnO/p-GaN diodes display a broad blue-violet emission centered at 430 nm, whereas the n-ZnO/ZnS/p-GaN and n-ZnO/AlN/p-GaN devices exhibit ultraviolet (UV) emission. Compared with the AlN interlayer, which is blocking both electron and hole at hetero-interface, the utilization of ZnS as intermediate layer can lower the barrier height for holes and keep an effective blocking for electron. Thus, an improved UV EL intensity and a low turn-on voltage (~5V) were obtained. The results were studied by peak-deconvolution with Gaussian functions and were discussed using the band diagram of heterojunctions.
School of Physics and Optoelectronic Engineering, Ludong University, Yantai 264025, China. phyzlc@163.com
Lichun
L
Zhang
Qingshan
Q
Li
Liang
L
Shang
Feifei
F
Wang
Chong
C
Qu
Fengzhou
F
Zhao
D004867:Equipment Design; D019544:Equipment Failure Analysis; D005708:Gallium / Q000737:chemistry*; D008029:Lighting / Q000295:instrumentation*; D008163:Luminescent Measurements / Q000295:instrumentation*; D008422:Materials Testing; D018036:Selenium Compounds / Q000737:chemistry*; D012666:Semiconductors; D014466:Ultraviolet Rays; D017967:Zinc Compounds / Q000737:chemistry*; D015034:Zinc Oxide / Q000737:chemistry*
D018036:Selenium Compounds; D017967:Zinc Compounds; C473348:gallium nitride; D005708:Gallium; C044696:zinc selenide; D015034:Zinc Oxide