Electrically pumped ultraviolet random lasing from heterostructures formed by bilayered MgZnO films on silicon

摘要

We report on electrically pumped ultraviolet random lasing (RL) from heterostructures formed by bilayered MgZnO films on silicon, where Mg_(0.15)Zn_(0.85)O and Mg_xZn_(1-x)O (x=0.25 or above) films act as the light-emitting and barrier layers, respectively. While, with a barrier layer composed of a Mg_(0.20)Zn_(0.80)O film, only spontaneous electroluminescence occurs in the heterostructures. It has thus been proved that a large enough conduction-band offset (△E_c) is necessary for the electrically pumped RL from the MgZnO film-based heterostructures. The △E_c required herein is estimated to be ～0.17 eV. The mechanism for the results as mentioned above has been tentatively elucidated.