Blue electroluminescence from ZnO based heterojunction diodes with CdZnO active layers

p-ZnO/i-CdZnO/n-ZnO was grown on n-type Si substrates by plasma-assisted molecular-beam epitaxy. Rectifying I-V curves show typical diode characteristics. Blue electroluminescence emissions at around 459 nm were observed when the diodes were forward-biased at room temperature. The emission intensity increases with the increase of the injection current. Temperature dependent electroluminescence measurements suggest that the peak positions of blue emissions represent the band gap of the CdZnO active layer, which changes with the temperature. (C) 2009 American Institute of Physics. [doi: 10.1063/1.3271770]