Detecting an exciton crystal by statistical means

in Physica B. Condensed Matter (2014), 441

We investigate an ensemble of excitons in a coupled quantum well excited via an applied laser field. Using an effective disordered quantum Ising model, we perform a numerical simulation of the ... [more ▼]

We investigate an ensemble of excitons in a coupled quantum well excited via an applied laser field. Using an effective disordered quantum Ising model, we perform a numerical simulation of the experimental procedure and calculate the probability distribution function P(M) to create M excitons as well as their correlation function. It shows clear evidence of the existence of two phases corresponding to a liquid and a crystal phase. We demonstrate that not only the correlation function but also the distribution P(M) is very well suited to monitor this transition. [less ▲]

Compositional dependence of Raman scattering and photoluminescence emission in Cu-Ga-Se films grown by MOCVD

in Physica B. Condensed Matter (2009)

Photoluminescence and Raman spectra of the ordered vacancy compound CuGa5Se8

in Physica B. Condensed Matter (2008)

We studied the photoluminescence (PL) and Raman properties of the ordered defect compound CuGa5Se8. Twelve peaks were detected from the room-temperature Raman spectra with the A1 mode around 160 cm-1. Due ... [more ▼]

We studied the photoluminescence (PL) and Raman properties of the ordered defect compound CuGa5Se8. Twelve peaks were detected from the room-temperature Raman spectra with the A1 mode around 160 cm-1. Due to the stress in the polycrystalline thin film the corresponding frequencies of the Raman modes of a CuGa5Se8 single crystal were slightly shifted. One broad asymmetric PL band at 1.788 and 1.765 eV was observed at 10 K in the PL spectra of CuGa5Se8 single crystal and polycrystalline layer, respectively. The temperature and laser power dependencies of the PL spectra were also studied. The shape and properties of the PL band assure the presence of potential fluctuations and the analyses of the PL data suggest that the emission is due to band-to-tail (BT) or band-toimpurity (BI) recombination. [less ▲]