Photomodulation spectroscopy and cyclotron resonance of Cd1−xMnxTe/CdTe semimagnetic and strained multi-quantum well structures

We report the photoluminescence studies of the strained CdTe/CdMnTe single quantum wells ͑SQWs͒ with large manganese of 0.367. The conduction band-offset ratio Q c of this structure is found to be 0.92Ϯ0.01. The band filling effect in this SQW is discussed in detail. Our experiments show that the excitonic transition dominates the whole measured temperature ͑20-200 K͒ in the well. The broadening of linewidth with temperature can be well explained by exciton-longitudinal-optical ͑LO͒ phonon coupling model and a quantitative approach is presented to explain the experimental fact that the strength of the exciton-LO phonon coupling is quite stronger in SQWs than that of multiple quantum wells. We demonstrate the main mechanism of the decrease in radiative QW recombination efficiency is due to the thermal excitation of excitons out of CdTe well, followed by nonradiative recombination in the CdMnTe barriers.

Section: Introductionmentioning

confidence: 99%

Photoluminescence studies of strained CdTe/Cd0.633Mn0.367Te single quantum wells

Shen

1996

Studies of photoreflectance spectra in Cd1−xMnxTe/CdTe superlattices with high compositions

Chen

Wang

Liang

et al. 2002

Cd 1−x Mn x Te/CdTe superlattices were grown by molecular beam epitaxy with a CdTe buffer layer on GaAs(001) substrate. Photoreflectance spectra were performed on Cd1−xMnxTe/CdTe superlattices with high compositions of x=0.4, 0.8 at room temperature and liquid nitrogen temperature. The exciton transitions related to the heavy (H) and light (L) holes of 11H, 11L, 22H, and 33H are observed. After taking into account the strain-induced and quantum confinement effects, the theoretical calculations are in good agreement with the photoreflectance measurement results except x=0.8 of 33H. Photoluminescence measurements were also performed at room temperature and low temperature in order to compare with our photoreflectance results. Our results show that the photoreflectance spectroscopy technique is a powerful probe for the study of quantized state structures in superlattices systems.

Optical properties of Cd1−xMnxTe∕Cd1−yMnyTe superlattices with high difference of Mn concentration between wells and barriers

Bellani

Stella

Chen

et al. 2005

We studied the optical properties of Cd1−xMnxTe∕Cd1−yMnyTe semiconductor superlattices with medium (x=0.3,y=0.01) and high (x=0.8,y=0) difference of the Mn concentration between wells and barriers, by means of photoluminescence and photoreflectance spectroscopy. Photoluminescence allows us to study the emission due to the fundamental heavy (H) hole 11H interminiband excitonic transition and evidences the emission characteristics. Photoreflectance reveals several heavy and light (L) holes interminiband excitonic transitions, up to the 33H. The experiments are in good agreement with the theory with an envelope-function approximation approach, taking into account strain effects due to lattice mismatch between wells and barriers. The combined use of photoluminescence and photoreflectance gives a complete information on the electronic configuration of these Cd1−xMnxTe∕Cd1−yMnyTe superlattices that can find specific applications in spintronic devices.