GaSe: A layer compound with anomalous valence band anisotropy

Ottaviani, G.; Canali, C.; Nava, F.; Schmid, P. E.; Mooser, E.; Minder, R.; Zschokke, I.

doi:10.1016/0038-1098(74)90396-2

Cited by 142 publications

(22 citation statements)

References 11 publications

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“…26 For GaSe, this is the case for holes, whereas for electrons the effective mass in the layer plane is about three times smaller than perpendicular to it. Experimental results for the effective mass of holes in GaTe point to similar effects: m electrons.…”

Section: Calculation Detailsmentioning

confidence: 95%

Ab initioguided optimization of GaTe for radiation detection applications

Leão

Lordi

2011

Phys. Rev. B

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The development of semiconductor-based radiation detectors that display high energy resolution while operating at room temperature is a pressing need for both scientific applications as well as homeland security. Practice has proven that the real performance of materials in such applications is often hindered by intrinsic defects and accidental impurities. Experimental efforts to improve the properties of such materials are both time consuming and costly, since they rely largely on trial and error. In this paper, the properties of gallium telluride (GaTe)-a high Z, moderate band gap semiconductor-are investigated for room-temperature radiation detection applications. Systematic theoretical modeling based on density functional theory calculations is used to suggest experimental processes to grow this semiconductor with optimal properties, by judiciously identifying the most detrimental native defects and devising ways to minimize their occurrence as well as compensating their electronic impact on the crystal. The analysis suggests that material grown Ga-rich would have significantly higher resistivity, carrier mobilities, and carrier lifetimes compared to Te-rich material. In addition, Ge doping and In doping can be effective for carrier compensation of the material. Doping with Ge can be especially effective, if the ambipolar nature of substitutional incorporation on both Ga and Te sites is exploited.

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Section: Calculation Detailsmentioning

confidence: 95%

Ab initioguided optimization of GaTe for radiation detection applications

Leão

Lordi

2011

Phys. Rev. B

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“…The spectra (b) and (c) were measured by exciting on the low-energy tail of the line DFE. During the energy scanning of the spectrometer the luminescence was stopped in a range of about 10 em-1 across the laser excitation [22] and reported in Table 2. The peak DFE, at 2.113 eV on the high-energy tail of the line DFE, is due to the radiative recombination of the DFE from the excited state n = 2, which can be thermally populated at 80 K. In fact the energy difference of these two lines is 15 meV, i.e.…”

Section: Resultsmentioning

confidence: 99%

Radiative Decay from Free and Bound Excitons in GaSe

Capozzi

Caneppele

Montagna

et al. 1985

Physica Status Solidi (b)

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Spontaneous excitonic luminescence in GaSe is investigated from 80 to 300 K and a t weak laser excitation intensity. Radiative recombinations of direct and indirect free excitons are clearly observed. The analysis of the emission lines as a function of the temperature, of the excitation intensity, and of laser energy permits to attribute two lines of the intrinsic luminecsence to the recombination of direct and indirect excitons bound to defect centres localized in the energy gap. On the basis of recent theories on exciton-impurity complexes, it is found that in the crystals the excitonic binding centres are deep neutral acceptors. From the dissociation energy of the bound excitons the ionization energy of the acceptor levels is estimated. Moreover, the measurements seem to indicate that thermal equilibrium between direct and indirect excitonic states is lacking below about 100 K.Die Spontane Exzitonenlumineszenz in GaSe wird zwischen 80 und 300 K und mit schwacher Laseranregungsintensitat untersucht. Strahlende Rekombination von direkten und indirekten freien Exzitonen wird deutlich beobachtet. Die Analyse der Emissionslinien in AbhLngigkeit von der Temperatur, der Anregungsintensitat und der Laserenergie erlaubt, zwei Linien der intrinsischen Lumineszenz der Rekombination von direkten und indirekten Exzitonen zuzuordnen, die an in der Energielucke lokalisierten Defektzentren gebunden sind. Auf der Grundlage neuerer Theorien zu Exziton-Storstellenkomplexen wird gefunden, dal3 in den untersuchten Kristallen die Exzitonenbindungszentren tiefe neutrale Akzeptoren sind. Aus der Dissoziationsenergie gebundener Exzitonen l&Bt sich die Ionisierungsenergie der Akzeptorniveaus berechnen. Dariiberhinaus scheinen die MeBergebnisse zu zeigen, dal3 unterhalb etwa 100 K kein thermisches Gleichgewicht mehr besteht zwischen direkten und indirekten Exzitonenzustiinden.

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“…Experiments [13] indicate that in this case, the geometric average of the hole effective masses is smaller than the average electron effective mass. Let us consider now the case of AgBr whose point group is 0,.…”

Section: Applicationsmentioning

confidence: 91%

Biexcitons in Indirect‐Gap Semiconductors: Applications to GaSe and AgBr

Quattropani

Forney

Bassani³

1975

Physica Status Solidi (b)

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The effective mass approximation for biexciton states is extended to semiconductors with indirect gap. An equation similar to that valid for direct-gap semiconductors is obtained for the envelope function. The electron-hole exchange contribution is formally the same as that for the direct-gap case. Intervalley interaction lifts the degeneracy of the biexciton ground state. The procedure is applied to the case of GaSe and AgBr, where the ground state multiplet of the biexcitons is related to the band structures.La derivation de 1'Bquation pour la fonction enveloppe du biexciton est Btendue aux semiconducteurs B bande interdite indirecte. On obtient une Bquation similaire B celle qui s'applique aux semiconducteurs B bande interdite directe. La contribution due B l'interaction d'bchange Blectron-trou est formellement la m6me. L'interaction entre vallBes non Bquivalentes lhve la dBgknBrescence de 1'Btat fondamental du biexciton. La mBthode dkveloppke est appliquee aux cas du GaSe et du AgBr. On peut ainsi relier la multiplicitk de 1'8tat fondamental du biexciton aux structures de bandes.

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GaSe: A layer compound with anomalous valence band anisotropy

Cited by 142 publications

References 11 publications

Ab initioguided optimization of GaTe for radiation detection applications

Ab initioguided optimization of GaTe for radiation detection applications

Radiative Decay from Free and Bound Excitons in GaSe

Biexcitons in Indirect‐Gap Semiconductors: Applications to GaSe and AgBr

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