Review of optical applications of CdTe

Bell, R. O.

doi:10.1051/rphysap:01977001202039100

Cited by 54 publications

(21 citation statements)

References 33 publications

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“…Both CdTe and BSO are Pockels cells. 18,19 The refractive index of a Pockels cell can be expressed as 17 E Q -T A R G E T ; t e m p : i n t r a l i n k -; e 0 0 1 ; 3 2 6 ; 2 5 6…”

Section: Methodsmentioning

confidence: 99%

Study of material properties important for an optical property modulation-based radiation detection method for positron emission tomography

2017

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Abstract. We compare the performance of two detector materials, cadmium telluride (CdTe) and bismuth silicon oxide (BSO), for optical property modulation-based radiation detection method for positron emission tomography (PET), which is a potential new direction to dramatically improve the annihilation photon pair coincidence time resolution. We have shown that the induced current flow in the detector crystal resulting from ionizing radiation determines the strength of optical modulation signal. A larger resistivity is favorable for reducing the dark current (noise) in the detector crystal, and thus the higher resistivity BSO crystal has a lower (50% lower on average) noise level than CdTe. The CdTe and BSO crystals can achieve the same sensitivity under laser diode illumination at the same crystal bias voltage condition while the BSO crystal is not as sensitive to 511-keV photons as the CdTe crystal under the same crystal bias voltage. The amplitude of the modulation signal induced by 511-keV photons in BSO crystal is around 30% of that induced in CdTe crystal under the same bias condition. In addition, we have found that the optical modulation strength increases linearly with crystal bias voltage before saturation. The modulation signal with CdTe tends to saturate at bias voltages higher than 1500 V due to its lower resistivity (thus larger dark current) while the modulation signal strength with BSO still increases after 3500 V. Further increasing the bias voltage for BSO could potentially further enhance the modulation strength and thus, the sensitivity.

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“…Both CdTe and BSO are Pockels cells. 18,19 The refractive index of a Pockels cell can be expressed as 17 E Q -T A R G E T ; t e m p : i n t r a l i n k -; e 0 0 1 ; 3 2 6 ; 2 5 6…”

Section: Methodsmentioning

confidence: 99%

Study of material properties important for an optical property modulation-based radiation detection method for positron emission tomography

2017

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“…The absorption coefficients of CdTe at these wavelengths are: cm cm and cm [19], [20]. The corresponding absorption depths of these radiations for CdTe do not differ so much: m m and m, respectively.…”

Section: Ellipsometric Proceduresmentioning

confidence: 99%

Characterization of Functional Layers of CdTe Crystals Subjected to Different Surface Treatments

Gnatyuk

Поперенко

Yurgelevych

et al. 2015

IEEE Trans. Nucl. Sci.

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The surface functional layers of commercial detectorgrade CdTe crystals are characterized after different surface treatments such as chemical polishing etching in bromine-containing solutions and laser annealing with nanosecond pulses of the second harmonic of a YAG:Nd laser. The effects of etching and laser irradiation with energy density near the melting threshold of CdTe on the optical properties of the CdTe crystal surface are studied using ellipsometry and photoluminescence (PL). The samples after storage in air are also investigated. The intrinsic emission band at 1.58 eV and broad dopant band peaked at 1.45 eV are observed in the PL spectra excited by a semiconductor laser with wavelength of 405 nm at 80 K. The low energy band is associated with carrier recombination at structural defects in the surface layer. The redistribution of the PL band intensities after chemical polishing is found and it is attributed to transformation of the point defect structure and defect formation in the surface region of CdTe. The laser treatment essentially changes the surface state and structure of the surface layer that can be used for effective modification of characteristics of the functional layers of CdTe crystals particularly band bending before formation of electrical contacts.

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“…Of the four materials named previously, CdTe has the highest electro-optic coefficient. [2][3][4] The Pockels effect, as it is usually called, allows electrical control of optical response characteristics, especially for transmission 5 but also for reflection. 6 Bulk CdTe crystals with high resistivity (>10 9 X cm) are successfully used in intracavity electro-optic modulators for Q-switched CO 2 lasers at 10.2 lm wavelength.…”

Section: Introductionmentioning

confidence: 99%

“…7 When an isotropic noncentrosymmetric material is subjected to a dc electric field E dc , the medium acts like an orthorhombic dielectric material. [2][3][4] In the Cartesian coordinate system ðx 1 ; x 2 ; x 3 Þ with the coordinate axes aligned with the crystallographic axes and fx 1 ;x 2 ;x 3 g is the right-handed triad of mutually orthogonal unit vectors, the relative permittivity dyadic e pc of the material may be stated as 6 e pc ¼ vðx 1x1 þx 2x2 Þ þ aðx 1x2 þx 2x1 Þ þ wx 3x3 ;…”

Section: Introductionmentioning

confidence: 99%

Giant enhancement of the controllable in-plane anisotropy of biased isotropic noncentrosymmetric materials with epsilon-negative multilayers

Valagiannopoulos

Tsitsas

Lakhtakia

2017

Journal of Applied Physics

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Effects of photon reabsorption phenomena in confocal micro-photoluminescence measurements in crystalline silicon J. Appl. Phys. 121, 063101063101 (2017) Giant in-plane anisotropy can be exhibited by a finitely thick periodic multilayer comprising bilayers of an isotropic noncentrosymmetric material and a non-dissipative isotropic medium of negative permittivity, when a dc electric field is applied in the thickness direction. Compared to a homogeneous layer of the noncentrosymmetric material with the same thickness as the periodic multilayer, the latter exhibits an effective in-plane anisotropy that can be three orders larger in magnitude. This enhancement gets more substantial at higher frequencies and is electrically controllable. The incorporation of dissipation reduces the enhancement of the effective in-plane anisotropy, which nevertheless remains significant. We expect the finitely thick periodic multilayer to be useful as a polarization transformer or a modulator in the terahertz regime fully controllable via external dc bias. Published by AIP Publishing. [http://dx

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Review of optical applications of CdTe

Cited by 54 publications

References 33 publications

Study of material properties important for an optical property modulation-based radiation detection method for positron emission tomography

Study of material properties important for an optical property modulation-based radiation detection method for positron emission tomography

Characterization of Functional Layers of CdTe Crystals Subjected to Different Surface Treatments

Giant enhancement of the controllable in-plane anisotropy of biased isotropic noncentrosymmetric materials with epsilon-negative multilayers

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