On the possibility of the exciton-phonon bound states in GaSe

Malik, Aisha; Litvinov, V. I.; Kovalyuk, Z. D.

doi:10.1016/0038-1098(80)90737-1

Cited by 4 publications

(2 citation statements)

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“…It is seen that the energy position of the main peak in the photoconductivity spectrum of doped GaSe crystals is similar to the peak position observed for undoped crystals and the peak energy is almost the same as the free exciton (n = 1) peak energy position of the absorption spectra. Observation of this peak is a result of the ionization of exciton states to free charge carriers and hence contributing to the photoconductivity [3,5,18]. As seen from Fig.…”

Section: Resultsmentioning

confidence: 84%

“…This behavior is related to the dopant atoms and the defects in the crystals, as they increase the concentration of photosensitive centers and recombination barriers. The complexes formed by Ge atoms and lattice imperfections in hcp GaSe crystals increase the concentration of slow recombination centers [3,6,7,15,16,[18][19][20]. The slow (r) and fast (s) recombination centers have big asymmetric cross sections; σ r /σ s ~ 10…”

Section: Resultsmentioning

confidence: 98%

See 1 more Smart Citation

Exciton photoconductivity in Ge‐doped GaSe crystals

Mamedov

Karabulut

Kodolbaş

et al. 2005

Physica Status Solidi (b)

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Spectral photoconductivity in Ge-doped GaSe crystals was investigated as a function of temperature. It is found that when the crystal is doped with small concentrations of Ge atoms (0.01 at%), the photoconductivity is carried out by the ionization of the excitons. In these crystals, exciton photoconductivity is found to have an Urbach tail similar to the tail observed in exciton absorption. Investigation of the temperature dependence of the peak positions (E exc (T)) and line widths (Г exc (T)) of the photoconductivity spectra indicates that the exciton ionization is due to the exciton-phonon and exciton-impurity interactions. From the analyses of the E exc (T) and Г exc (T) data, it is found that at low temperatures (T < 50 K) the exciton-phonon interaction takes place via rigid-layer phonon modes while in the 50 -300 K temperature range it takes place via phonons with hν p ≈ 18 meV. In the 300 -450 K range the energy of the phonons involved in the exciton-phonon interaction is hν p ≈ 36 meV. The anisotropy observed in the exciton photoconductivity taken parallel and perpendicular to the layers of doped GaSe crystals diminishes at T = 300 K and the peak positions of the photoconductivity in both directions coincide with the peak position of the free exciton peak (n = 1) in the absorption spectrum. Another important result found is that in these layered GaSe crystals the exciton states continue to exist at high temperatures, up to 450 K.

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Section: Resultsmentioning

confidence: 84%