H. Męczyńska

Growth and characterisation of bulk Zn1−xBexSe, Zn1−x−yMgxBeySe and Zn1−xBexTe crystals

Abstract In this paper we report an extension of our earlier results for Zn 1− x Mg x Se and low-Be Zn 1− x Be x Se to related ternary (high-Be Zn 1− x Be x Se and Zn 1− x Be x Te) and quaternary (Zn 1− x − y Mg x Be y Se) alloys. A dependence of defect structure on crystal composition, growth and thermal treatment is observed. X-ray diffraction was used for phase analysis and determination of lattice parameters. High-resolution transmission electron microscopy was used to compare kind and density of defect. Among the studied crystals, the lowest defect density was found for Zn 1− x − y Mg x Be y Se.

Optical characterization of Zn 0.95 − x Be x Mn 0.05 Se mixed crystals

A systematic study of a series of

Temperature-dependent photoluminescence characterization of Cd1−x−yBexZnySe mixed crystals

{\text{Zn}}_{0.95\ensuremath{-}x}{\text{Be}}_{x}{\text{Mn}}_{0.05}\text{Se}

Optical characterization of Cd1−x−yBexZnySe mixed crystals

mixed crystals with different Be content

Temperature dependence of the edge excitonic transitions of the wurtzite Cd1−x−yBexZnySe crystals

(0.05\ensuremath{\le}X\ensuremath{\le}0.20)

Photoluminescence and electromodulation spectroscopy characterization of a Zn0.81Be0.04Mg0.15Se mixed crystal

grown by the modified high-pressure Bridgman method were carried out by room-temperature surface photovoltage spectroscopy (SPS), temperature-dependent photoluminescence (PL), and contactless electroreflectance (CER). A typical PL spectrum at low temperature consists of free exciton line, an edge emission due to recombination of shallow donor-acceptor pairs, and the

Optical characterization of Zn0.96Be0.04Se and Zn0.93Mg0.07Se mixed crystals

{\text{Mn}}^{2+}

Hall effect investigations of Cd1−xMgxSe and Zn1−xMgxSe bulk crystals

-related intraionic emission. The near band-edge transition energies determined by analyzing the CER and SPS spectra showed a blueshift with the increase in Be content. The peak positions of band-edge exciton features in the PL spectra shifted slightly toward lower energies as compared to the corresponding transition energies obtained from CER and SPS data. The observed increases in the CER-PL shift with the increasing of Be content are explained by the increasing compositional disorder causing the smearing of the band-edge energies. The excitonic line broadening for the samples with larger Be/Zn ratio are attributed in part to the alloy-scattering effects and also to the poorer crystalline quality of the samples with higher content of Be. In addition, the parameters that describe the temperature dependence of the transition energies and broadening parameters of the band-edge excitonic transitions were evaluated and discussed.

Temperature dependence of energies and broadening parameters of near band edge interband excitonic transitions in wurtzite ZnCdMgSe

Temperature-dependent photoluminescence (PL) characterization of a series of wurtzite-type Cd1−x−yBexZnySe mixed crystals has been carried out in the temperature range between 15 and 300 K. The samples were grown by the modified high pressure Bridgman method. A typical PL spectrum at low temperature consists of an exciton line, an edge emission due to recombination of shallow donor–acceptor pairs and a broad band related to recombination through deep level defects. The peak positions of the excitonic emission line in the PL spectra correspond quite well to the transition energies of exciton A from previously reported electromodulation reflectance data (Liu et al 2005 J. Appl. Phys. 98 083519). The parameters that describe the temperature dependence of the transition energy and broadening parameter of the band-edge excitonic emission are evaluated and discussed.

Photoacoustic study of Cd1-x-yBexMnyTe mixed crystals

A detailed optical characterization of a series of wurtzite-type Cd1−x−yBexZnySe mixed crystals grown by the modified high pressure Bridgman method has been carried out via photoluminescence (PL) and contactless electroreflectance (CER) in the temperature range of 15–300 K. Room temperature surface photovoltage spectroscopy has been used as a diagnostic technique for checking the surface condition of the sample. For the mechanically polished sample, the surface photovoltage spectrum at room temperature recorded a below band edge broad feature which is most likely related to the surface states induced by mechanical defect. This feature can be eliminated via mechanical polishing and followed by chemical etching, and hence, only the exciton line was observed for the damage-removed sample. Typical PL spectrum at low temperature consists of an exciton line, an edge emission due to recombination of shallow donor-acceptor pairs, and a broadband related to recombination through deep level defects. Various interba...