Midinfrared intersubband absorption in ZnxCd1-xSe/Znx'Cdy'Mg1-x'-y'Se multiple quantum well structures

The authors report the observation of intersubband absorption in ZnxCd(1-x)Se/Znx'Cdy'Mg(1-x'-y')Se multiple quantum wells. Lattice-matched samples were grown by molecular beam epitaxy on InP (001) substrates. Photoluminescence measurements indicate that the samples have excellent material quality. The peak absorption wavelengths measured by Fourier transform infrared spectroscopy are 3.99 and 5.35 mu m for two samples with ZnxCd(1-x)Se well widths of 28 and 42 angstrom, respectively. These values fall within the 3-5 mu m wavelength range, which is of interest for midinfrared intersubband devices, such as quantum cascade lasers and quantum well infrared photodetectors. Their experimental results fit well with theoretical predictions based on the envelope function approximation. The results indicate that these wide band gap II-VI materials are very promising for midinfrared intersubband device applications. (c) 2006 American Institute of Physics.