Electroabsorption and Non-Equilibrium Carrier Recombination in CdGa2S4 Single Crystals

Optical-absorption and photoluminescence ͑PL͒ spectra have been measured on the defect-chalcopyrite-type semiconductor CdGa 2 Te 4 in the 0.9-1.5-eV photon-energy range at temperatures between 11 and 300 K. The temperature dependence of the direct-gap energy of CdGa 2 Te 4 has been determined from the optical-absorption spectra and fit using the Varshni equation and an analytical four-parameter expression developed for the explanation of the band-gap shrinkage effect in semiconductors. The PL spectra show an asymmetric emission band peaking at ϳ1.326 eV and a symmetric emission band at ϳ1.175 eV at T = 11 K, which are attributed to donor-acceptor-pair recombination between exponentially tailed or Gaussian-like donor states and acceptor levels, respectively. A multiple-exponential fit analysis of the PL emission suggests acceptor levels of 50 and 86 meV and a deep donor level of 190 meV, together with an unidentified shallow level of 9 meV. An energy-band scheme has been proposed for the explanation of PL emission observed in CdGa 2 Te 4 .

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“…1 Most of these compounds have defect-chalcopyrite ͑space group= S 4 2 ͒ or defect stannite ͑space group= D 2d 11 ͒ structure.…”

Section: Introductionmentioning

confidence: 99%

Optical absorption and emission in the defect-chalcopyrite semiconductor CdGa2Te4

Ozaki

Muto

Nagata

et al. 2005

Journal of Applied Physics

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“…[2][3][4][5] In this particular compound, the presence of Mn ions adds a magnetic behavior that opens the way to magneto-optical properties. In view of its technological interest, it would be convenient to have a complete characterization of its optical and electronic properties.…”

Section: Introductionmentioning

confidence: 99%

Raman selection rules in uniaxial media: The nonpolar modes ofMnGa2Se4

2005

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It is known that optically anisotropic media can change the polarization of light propagating inside them. As regards Raman spectroscopy, this affects the light intensity measured in different geometrical configurations and results in an apparent unfulfillment of selection rules. We present an experimental and theoretical study of such effects in the defect chalcopyrite semiconductor MnGa 2 Se 4 . Optical anisotropy is taken into account by including in the calculation of Raman intensities the phase difference appearing between ordinary and extraordinary waves as they propagate, in uniaxial media, with different velocities. Birefringence can be obtained from Raman measurements provided that the distance run by the light is known.

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“…Some device structures like tunable filters on CdGa 2 S 4 and UV photodetectors on CdAl 2 S 4 have already found practical applications. 1,2 Structural studies of semiconductors present increasing interest in relation to pressure-induced phase transitions, in particular. Numerous studies of II-VI, III-V, and IV-IV compounds have imposed the general understanding of transitions and high-pressure phases, and established structural systematics within each of these systems.…”

Section: Introductionmentioning

confidence: 99%

Phase transitions in defect chalcopyrite compounds under hydrostatic pressure

et al. 1999

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Tetrahedrally bonded AGa 2 X 4 (AϭCd, Zn; XϭS, Se͒ compounds crystallizing in defect chalcopyrite and defect famatinite structures have been studied by Raman spectroscopy under hydrostatic pressure. The pressure-induced changes in the Raman spectra of both ordered defect chalcopyrite and partially disordered defect famatinite structures were attributed to an order-disorder phase transition in the cation sublattice, which proved to occur in two stages, as predicted by Bernard and Zunger ͓Phys. Rev. B 37, 6835 ͑1988͔͒. The first stage of the transition was found to depend on the tetragonal distortion of the initial crystals. An irreversible disappearance of Raman signal at elevated pressures was observed and attributed to a phase transition from the adamantine structure to a high-symmetry rocksalt-type structure. The pressure of this transition in the compounds under consideration exhibits a dependence on bond ionicity and bond length. The structure of decompressed samples was explained on the basis of pressure dependence of potential barriers for the phase transition by using a configuration-coordinate model.

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Electroabsorption and Non-Equilibrium Carrier Recombination in CdGa2S4 Single Crystals

Cited by 31 publications

References 9 publications

Optical absorption and emission in the defect-chalcopyrite semiconductor CdGa2Te4

Optical absorption and emission in the defect-chalcopyrite semiconductor CdGa2Te4

Raman selection rules in uniaxial media: The nonpolar modes ofMnGa2Se4

Phase transitions in defect chalcopyrite compounds under hydrostatic pressure

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