Lithium-related point defects in CdTe

Zielińska, R.; Król, Andrzej; Nazarewicz, W.

doi:10.1088/0022-3719/17/29/020

Cited by 10 publications

(4 citation statements)

References 16 publications

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“…This value of k is also very close to those obtained for other impurities such as Ca and Mg at a Te site in CdTe, further confirming the results of our analyses and interpretations for the assignments of the related absorption peaks. The parameters of the perturbation theory [Equation (2)] also seem to be in good agreement with those obtained for other impurity atoms such as Mg at Te sites. We were able to make the first identification and analyses of the fundamental ν 0 local vibrational mode of 17 O and 18 O isotopes.…”

Section: Discussionsupporting

confidence: 72%

“…Hence, the only possible transitions to the first and second excited states are of the form Γ 1 → Γ 5 . Table 2 gives the calculated parameters (force constants) k, B, D 1 , D 2 , and the lattice effective mass M L of the theoretical energy levels, given by Equation (2). These parameters were found by treating them as Table 1.…”

Section: Resultsmentioning

confidence: 99%

“…LVMs arise when an impurity atom at a substitutional site is much lighter than any of the host atoms in elemental and compound semiconductors provided that the force constant strengths between the impurity and the host atoms are not much different from those among the host atoms themselves [1]. For example, Li impurities in CdTe replacing either Cd or Te atoms of the host produce well defined localized vibrational modes [2]. Many local modes of light impurities are reported in the literature, such as those of Be in ZnTe, ZnSe, ZnS, and CdTe [3][4] and those of S, Be, and Mg in Zn x Cd 1−x Te [5].…”

Section: Introductionmentioning

confidence: 99%

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Local vibrational modes of natural isotopes of substitutional oxygen in CdTe

Tarhan¹,

Ramdas²

2020

Turk J Phys

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We investigated the localized vibrational modes (LVM) of natural oxygen containing 16 O, 17 O, and 18 O isotopes at a substitutional tellurium site in cadmium telluride using infrared absorption spectroscopy at cryogenic temperatures. The main absorption peak observed at 350 cm −1 was formerly attributed to a fundamental LVM mode ( ν0) of oxygen at a tellurium site. The relatively weak absorption peaks observed at 331 cm −1 and 340 cm −1 are assigned as the same ν0 mode of the 17 O and 18 O isotopes, respectively, based on their relative intensities and spectral positions.The spectral positions were confirmed with theoretical calculations using a linear chain model where the peak position at 350 cm −1 was taken as the reference for the 16 O isotope. From a least square analysis of the observed peak positions we were able to calculate the force constants from perturbation theory. A Lorentzian line shape analysis of each ν0 absorption peak, considering the effects of isotopic mass and natural abundance variations of the host Cd atoms, was also carried out to further confirm their assignments. Reasonably good line shape fittings were obtained for ν0 modes of all isotopes of oxygen.

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Section: Discussionsupporting

confidence: 72%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Local vibrational modes of natural isotopes of substitutional oxygen in CdTe

Tarhan¹,

Ramdas²

2020

Turk J Phys

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“…Li impurities are well known examples due to their small masses. In CdTe they give rise to LVM's upon replacing either Cd or Te atoms [7]. Local modes of such light impurities are well reported in the literature, such as those of Be in ZnTe, ZnSe, ZnS, and CdTe and those of S, Be, and Mg in ZnxCd1-xTe [5,6].…”

Section: Introductionmentioning

confidence: 86%

Host isotope effects on the oxygen local vibrations in CdTe

Tarhan,

Ramdas

2023

Phys. Scr.

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Strong absorption peak observed near 350 cm-1 in the infrared spectrum of CdTe is assigned to a localized vibrational mode of 16O impurity atoms at tellurium sites. In this work, we studied the nature of these vibrations in terms of the effect of isotopic mass variations in the nearest neighbor (NN) Cd atoms. We showed that Cd atoms with 8 stable natural isotopes of varying abundances cause the observed line shape in the observed LVM absorption peak. To calculate the effect of isotopic mass variations, we used the XY4 molecular model, X being the impurity atom at a host Te atom site and Y’s are various isotopes of the host Cd atoms. Corresponding frequencies of LVM modes were calculated for each possible combinations of NN Cd atoms. For an XY4 molecule with Td symmetry, only the triply degenerate Γ5 mode is infrared active. The energies of this mode are higher than those of the others. This mode is possible only when all NN Cd atoms are the same isotope. To simulate the absorption data, we used a dynamical matrix approach where a force constant is given for each of the bending and stretching potential energy terms. By diagonalization of the dynamical matrix we were able to fit the calculated spectrum to the data with a proper choice of the bending and stretching force constants. A good agreement with the experiment as well as reported force constants for other impurities in CdTe is obtained.

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Point Defects in CdTe Containing Simultaneously Lithium and a Group IV Impurity

Zielinska-Purgal¹,

Piwowarczyk²,

Nazarewicz³

1994

Physica Status Solidi (b)

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Infrared absorption associated with localized vibrational modes in CdTe containing both Li and a group IV impurity (Si, Ge, or Sn) is studied. On the basis of the obtained experimental results it is established that the following point defects play a dominant role: 1. isolated Li,,, 2. Licd-Lii nearest-neighbour pairs, and 3. Li,,-M,, next-nearest-neighbour pairs, where M,, denotes a Si, Ge, or Sn impurity at a Cd site. It is also found that some localized vibrational modes of Licd-Mc, pairs are connected with the coupled motion of Li,, and M,, impurities and that the model of a weakly coupled impurity pair, usually used to analyze experimental results, is not applicable in this case.L'absorption infrarouge associee aux modes localises est etudie dans le CdTe containant en m2me temps les impuretes de lithium et les impuretes du groupe IV (Si, Ge, ou Sn). Sur la base des resultats obtenus on a etablie que les defauts suivants jouent un r6le dominant: 1. Li,, isole, 2. paires Li,,-Li, avec les atomes en positions de premikres voisins, et 3. paires Licd-M,, avec les atomes en positions de second voisins, ou M,, designe une impurete de Si, Ge ou Sn remplaqante un atome de cadmium. On a aussi constate que certains modes localists des paires Licd-Mcd sont associes au mouvement couple des impuretes Li,, et M,, et que le modele d'une paire faiblement couplee, habituellement utilise dans l'analyse des resultats exptrimentaux, est inapplicable dans ce cas.

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Lithium-related point defects in CdTe

Cited by 10 publications

References 16 publications

Local vibrational modes of natural isotopes of substitutional oxygen in CdTe

Local vibrational modes of natural isotopes of substitutional oxygen in CdTe

Host isotope effects on the oxygen local vibrations in CdTe

Point Defects in CdTe Containing Simultaneously Lithium and a Group IV Impurity

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