Use of contactless electroreflectance in the development of quantum cascade lasers from ZnCdSe/ZnCdMgSe



Electro-modulation techniques have been used extensively to analyze interband transitions in materials and devices, however little has been done to use these techniques for the analysis of intersubband transitions in materials and devices. In this work, contactless electroreflectance has been used to determine the conduction band offset of ZnCdSe/ZnCdMgSe quantum well structures. Toward the development of quantum cascade lasers, multi-quantum well structures with intersubband absorption at 178 meV were analyzed using contactless electro-reflectance. Finally, quantum cascade laser structures were designed for emission at 4.8 μm. The multi-quantum well structures presented an excellent agreement between the designed and measured absorption and emission, respectively. This work demonstrates that contactless electro-reflectance can accurately determine the conduction band offset and is useful in the analysis of intersubband transitions. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)