Vanadium in CdTe: An electron-paramagnetic-resonance study

Christmann, P.; Meyer, Bernhard; Kreissl, J.; Schwarz, R.

doi:10.1103/physrevb.53.3634

Cited by 27 publications

(16 citation statements)

References 15 publications

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“…The value of the segregation coefficient is a little above 1. This result is in disagreement with [20], where the segregation coefficient a little below 1 was found (which also means weak segregation, but in the opposite direction).…”

Section: Resultscontrasting

confidence: 81%

Semi‐insulating (Cd,Mn)Te:V crystals: Electrical contacts

Witkowska-Baran¹,

Mycielski²,

Szadkowski³

et al. 2007

Physica Status Solidi (b)

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The high-resistivity (Cd,Mn)Te is believed to be suitable to succesfully replace the commonly used (Cd,Zn)Te system as a material for manufacturing large-area X-and γ-ray detectors. The purpose of our study was to elaborate a method of preparing high quality (Cd,Mn)Te crystal plates as well as a technique of producing good electrical contacts to that material. (Cd,Mn)Te was grown using the Bridgman method. The crystals were doped with vanadium to the level of 10 16 cm -3 . The crystals are twinned in the (111) plane, but by slicing the crystal parallel to the twinning plane we obtained monocrystalline plates of large area (e.g. 30 × 30 mm 2 ), which is essential for application purposes. Proper annealing of those plates in cadmium vapours allowed us to reduce the number of cadmium vacancies forming during the growth process. Due to the vanadium dopant acting as a compensating centre we obtained a semi-insulating material. In order to obtain good contacts to the (Cd,Mn)Te plates we used the method proposed initially for CdTe by Rioux et al. The ZnTe : Sb layers (~1 µm thick) were grown on the epi-ready (Cd,Mn)Te : V plates by the MBE technique. The grown layers were p-type and formed a good electrical contact to the crystal plates. Finally -a standard technique was used to cover the ZnTe layer by a metal layer. The contacts formed on (111) surfaces of (Cd,Mn)Te were studied. We believe that the contacts to the (111) surface are important for applications. In the paper we describe techniques of preparing electrical contacts and results of their characterization.

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Section: Resultscontrasting

confidence: 81%

Semi‐insulating (Cd,Mn)Te:V crystals: Electrical contacts

Witkowska-Baran¹,

Mycielski²,

Szadkowski³

et al. 2007

Physica Status Solidi (b)

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“…Next, we consider the proportionality relation 51 K d = A iso χ d /N A , where A iso is the isotropic core-polarization term in the hyperfine coupling of vanadium and N A is the Avogadro number. From the electron spin resonance of the V 3+ ion 37,38 , we take A iso = −85 kOe/µ B to obtain χ d = 6 ×10 −5 emu/mol, which corresponds to a density of states g(E F ) ≈ 2.0 states eV −1 cell −1 . We finally obtain χ orb = χ 0 − χ d ≈ 2 × 10 −4 emu/mol, comparable with the values reported in the related compound LiVO 2 39 .…”

Section: Nmr Measurementsmentioning

confidence: 99%

Possible phase separation and weak localization in the absence of a charge-density wave in single-phase1T-VS2

et al. 2014

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We report on a systematic study of the structural, magnetic and transport properties of highpurity 1T-VS 2 powder samples prepared under high pressure. The results differ notably from those previously obtained by de-intercalating Li from LiVS 2 . First, no Charge Density Wave (CDW) is found by transmission electron microscopy down to 94 K. Though, ab initio phonon calculations unveil a latent CDW instability driven by an acoustic phonon softening at the wave vector q CDW ≈ (0.21,0.21,0) previously reported in de-intercalated samples. A further indication of latent lattice instability is given by an anomalous expansion of the V-S bond distance at low temperature.Second, infrared optical absorption and electrical resistivity measurements give evidence of non metallic properties, consistent with the observation of no CDW phase. On the other hand, magnetic susceptibility and NMR data suggest the coexistence of localized moments with metallic carriers, in agreement with ab initio band structure calculations. This discrepancy is reconciled by a picture of electron localization induced by disorder or electronic correlations leading to a phase separation of metallic and non-metallic domains in the nm scale. We conclude that 1T-VS 2 is at the verge of a CDW transition and suggest that residual electronic doping in Li de-intercalated samples stabilizes a uniform CDW phase with metallic properties.

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“…EC-0.86 [9] EC-0.75 [10] EV+0.55 [11] EV+1.4 (calc) [13] EV+0.71 [14] EV+0.95 [15] EV+(0.03-0.1) (calc) [16] EV+0.73 (assumed) [17] <(EV+0.47) [18] EV+0.74 (assumed) [17,5] EV+0.35 (calc) [19] Capture cross-section σ (cm 2 )…”

Section: Introductionmentioning

confidence: 99%

Characterization of compensation and trapping in CdTe and CdZnTe: Recent advances

Babentsov

Franc²,

Höschl

et al. 2009

Cryst. Res. Technol.

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Results on the properties of the known impurities, Ge, Sn, V and Bi, and the lattice imperfections, V Cd and Te Cd are summarized. We discuss their role in compensation, and in buffering the variations in shallow electronic levels in the grown ingot. We demonstrate that (~2-3 kT) variations of the Fermi energy increases carrier trapping to the deep levels. Trapping is manifest in a photoconductivity signal that can be studied by photoconductivity methods, thus allowing to monitor the spectroscopic-grade material before fabricating the detectors. Our approach could be important in preventing the after-glow effect and polarization. Dedicated to Prof. Wolfgang Neumann on the occasion of his 65th birthday

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Vanadium in CdTe: An electron-paramagnetic-resonance study

Cited by 27 publications

References 15 publications

Semi‐insulating (Cd,Mn)Te:V crystals: Electrical contacts

Semi‐insulating (Cd,Mn)Te:V crystals: Electrical contacts

Possible phase separation and weak localization in the absence of a charge-density wave in single-phase1T-VS2

Characterization of compensation and trapping in CdTe and CdZnTe: Recent advances

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