Room Temperature Confinement and Photoluminescence in HgCdTe Multiple Quantum Wells

We have grown HgCdTe/CdTe Multiple Quantum Wells (MQW) with the lowest transition near 3 µm, and we have observed room temperature confinement and photoluminescence. HgCdTe/CdTe MOW’S of different compositions can be used over the entire infrared range, since the material is lattice matched from 0 to 1.5 eV. The importance of the 3 µm region comes from the possibility of a communications system operating with fluoride fibers. The MQW was grown by MBE with 50 periods of 100 A of Hg0.15Cd0.85Te barriers and 50 A of Hg0.73Cd0.27Te wells (1). Transmission Electron Microscopy (TEM) and X-ray data confirm very little interdiffusion and high reproducibility of layer thickness. The thick barriers are necessary for strong confinement, especially for the light hole. Therefore we can see the heavy and light hole to conduction band transitions. The separation between these two transitions is mainly determined by the value of the valence band offset (VBO) between HgTe/CdTe, a controversial parameter with reported values ranging from 40 to 400 meV (2), and suggestions of being temperature dependent. Our data support a value near 400 mev which has little or no temperature dependence.