Tensile-strained Ge/SiGe multiple quantum wells (MQWs) were grown on a Ge-on-Si virtual substrate using ultrahigh vacuum chemical vapor deposition on an n+-Si (001) substrate. Direct-bandgap electroluminescence from the MQWs light emitting diode was observed at room temperature. The quantum confinement effect of the direct-bandgap transitions is in good agreement with the theoretical calculated results. The redshift mechanism of emission wavelength related to the thermal effect is discussed.
Project supported by the National Basic Research Program of China (Grant No. 2013CB632103), the National Natural Science Foundation of China (Grant Nos. 61036003, 61176013, and 61177038), and the High Technology Research and Development Program of China (Grant No. 2011AA010302).
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