Study of intersubband transitions of Zn_xCd_(1-x)Se/Zn_(x') Cd_(y') Mg_(1-x'-y') Se multiple quantum wells grown by molecular beam epitaxy for midinfrared device applications

摘要

Two Zn_xCd_(1-x)Se/Zn_(x')/Cd_(y')/Mg_(1-x'-y')Se multiple quantum well structures were grown by molecular beam epitaxy. The quantum well layer thickness of the multiple quantum well region was varied in order to tune the intersubband transition energy. The high crystalline quality of the material was demonstrated by high resolution x-ray diffraction. Contactless electroreflectance (CER) spectroscopy and Fourier transform infrared (FTIR) spectroscopy were used to characterize the intersubband transitions. Excellent agreement between the estimated value obtained by CER and the value measured by FTIR was achieved. Intersubband absorption at 6.89 and 5.37μm was observed demonstrating the ability to tune the properties of these wide band gap Ⅱ-Ⅵ materials for mid-IR intersubband device applications.