Charged Excitons and Biexcitons in CdZnTe/(Cd,Zn,Mn)Te Quantum Wells in Pulse Magnetic Fields

Abstract

We have studied exciton complexes such as charged excitons and biexcitons in dilute magnetic semiconductor Cd 1Àx Zn x Te/Cd 1ÀxÀy Zn x Mn y Te (x ¼ 0:07, y ¼ 0:43) quantum wells (well widths 4 and 9 nm). Laser excitation power dependence and time-resolved photoluminescence (PL) showed unique features related to excitons, charged excitons, and biexcitons. Four-wave-mixing spectroscopy with different choices of polarized incident light exhibited beating signals arising from exciton-biexciton interaction. Circular polarized PL was measured in magnetic fields of up to 42 T using a pulse magnet. The observed Zeeman splitting and the degree of circular polarization in magnetic fields revealed that the formation of biexcitons is quenched upon applying a magnetic field, and PL from the charged excitons was preserved up to the highest magnetic field.

Magneto-optical study ofn-type modulation-dopedZnO/MgxZn1−xMakino1, Furuta2, Segawa3 et al. 2009Phys. Rev. B11140View full textAdd to dashboardCite

“…An asymmetric line shape of the PL peak with a tail toward the lowerenergy side is rather typical of charged exciton transition, obeying an inverse Boltzmann function convoluted with a Gaussian function representing the fluctuations. 26 This is because even a negatively charged exciton of large wave vector ͑k vector͒ may recombine in its decay process, the mismatch in wave vector between the charged exciton and the photon being given to the electron. The relevant equation should take the form 26 FIG.…”

“…26 This is because even a negatively charged exciton of large wave vector ͑k vector͒ may recombine in its decay process, the mismatch in wave vector between the charged exciton and the photon being given to the electron. The relevant equation should take the form 26 FIG. 3.…”

Second hidden triplet-singlet crossover of charged excitons inn-doped (Cd,Mn)Te/(Cd,Mg)Te in ultra-high magnetic fields

“…However, a biexciton cannot be formed in such high magnetic field due to the same reason discussed in Ref. 45.…”