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11 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2026

Optical functions of crystalline and amorphous TeO2

The optical functions of crystalline paratellurite (α-TeO2) and amorphous TeO2 were determined using several optical techniques: (1) standard spectroscopic two-modulator generalized ellipsometry (2-MGE) of paratellurite (200–850 nm, 6.2–1.46 eV), (2) near-normal-incidence two-modulator generalized ellipsometry microscopy (2-MGEM) of paratellurite (577 nm, 2.15 eV), (3) Mueller matrix transmission of paratellurite (320–798 nm, 3.87–1.55 eV), and (4) polarized transmission of paratellurite (323.6–334.3 nm, 3.83–3.71 eV). The 2-MGE measurements yielded highly accurate values of the dielectric functions and error estimates from 1.46 to 6.2 eV for both paratellurite and amorphous TeO2, whereas the polarization-dependent transmission yielded more accurate values of the absorption coefficient below the band edge of paratellurite. The 2-MGEM measured the diattenuation of paratellurite, which is related to the birefringence. Mueller matrix transmission measurements of paratellurite of a (001) cut crystal as a function of angle of incidence were used to determine both the birefringence and the rotary power as a function of photon energy.

Jellison Jr, Gerald [ORNL]↗
DOE OSTI2020

Materials Data on TeO2 by Materials Project

TeO2 crystallizes in the orthorhombic Pbca space group. The structure is two-dimensional and consists of two TeO2 sheets oriented in the (0, 0, 1) direction. Te4+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Te–O bond distances ranging from 1.93–2.71 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to two equivalent Te4+ atoms. In the second O2- site, O2- is bonded in a 2-coordinate geometry to three equivalent Te4+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TeO2 by Materials Project

TeO2 is Rutile structured and crystallizes in the tetragonal P4_2/mnm space group. The structure is three-dimensional. Te4+ is bonded to six equivalent O2- atoms to form a mixture of corner and edge-sharing TeO6 octahedra. The corner-sharing octahedral tilt angles are 50°. There are two shorter (2.18 Å) and four longer (2.23 Å) Te–O bond lengths. O2- is bonded in a distorted trigonal planar geometry to three equivalent Te4+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TeO2 by Materials Project

TeO2 crystallizes in the tetragonal P4_32_12 space group. The structure is three-dimensional. Te4+ is bonded in a 4-coordinate geometry to four equivalent O2- atoms. There are two shorter (1.91 Å) and two longer (2.16 Å) Te–O bond lengths. O2- is bonded in a 2-coordinate geometry to two equivalent Te4+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TeO2 by Materials Project

TeO2 crystallizes in the tetragonal P4_12_12 space group. The structure is three-dimensional. Te4+ is bonded in a 4-coordinate geometry to four equivalent O2- atoms. There are two shorter (1.91 Å) and two longer (2.16 Å) Te–O bond lengths. O2- is bonded in a 2-coordinate geometry to two equivalent Te4+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TeO2 by Materials Project

TeO2 crystallizes in the orthorhombic P2_12_12_1 space group. The structure is three-dimensional. Te4+ is bonded in a 4-coordinate geometry to four O2- atoms. There are a spread of Te–O bond distances ranging from 1.91–2.17 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Te4+ atoms. In the second O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Te4+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TeO2 by Materials Project

TeO2 crystallizes in the orthorhombic P2_12_12_1 space group. The structure is three-dimensional. Te4+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Te–O bond distances ranging from 1.88–2.79 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Te4+ atoms. In the second O2- site, O2- is bonded in a distorted bent 120 degrees geometry to three equivalent Te4+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TeO2 by Materials Project

TeO2 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are three inequivalent Te4+ sites. In the first Te4+ site, Te4+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Te–O bond distances ranging from 1.92–2.99 Å. In the second Te4+ site, Te4+ is bonded in a 5-coordinate geometry to four O2- atoms. There are a spread of Te–O bond distances ranging from 1.92–2.50 Å. In the third Te4+ site, Te4+ is bonded to five O2- atoms to form edge-sharing TeO5 square pyramids. There are a spread of Te–O bond distances ranging from 1.93–2.16 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to three Te4+ atoms. In the second O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two Te4+ atoms. In the third O2- site, O2- is bonded in a distorted water-like geometry to three Te4+ atoms. In the fourth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two Te4+ atoms. In the fifth O2- site, O2- is bonded in a 3-coordinate geometry to three Te4+ atoms. In the sixth O2- site, O2- is bonded in a 2-coordinate geometry to three Te4+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Oxides related to cadmium telluride solar cells

Polycrystalline cadmium telluride (CdTe) is a leading material in photovoltaic technology due to its high absorption coefficient and near-optimum bandgap of 1.44 eV. It is known that CdTe film processing can promote surface oxidation depending on the growth environment and upon exposure to different oxidation conditions. For example, CdTeO3 forms when the CdTe film is treated in heated dry air, while in humid air, CdTe2O5 is detected. These oxides feature tellurium in the oxidation state +4 compared to the +2 state in CdTe. Other possible relevant oxides are CdO, TeO2, and TeO3. Using hybrid density functional calculations, we studied the electronic structure of these oxide materials and their band alignment to CdTe, which are essential parameters in the characterization of the interfaces at grain boundaries. The goal is to understand their stability and possible effects on passivating grain boundaries. The results are compared to the available experimental data.

14 SOLAR ENERGY↗
DOE OSTI2025

Baseline Hypothetical Facility for the Production of 131 I and 99 Mo using Activation Targets

This report describes a hypothetical facility for production of medical radioisotopes via activation under the Proliferation Resistance and Optimization (PRO-X) program. The facility uses neutron activation of non-special nuclear material (SNM) to produce the medical isotopes 131 I and 99 Mo at a throughput of 60 Ci/week of 131 I and 5 Ci/week of 99 Mo. The hypothetical design was carried out using a 10 MWt research reactor. The precursors used for the activation process were TeO2 for 131 I and MoO 3 for 99 Mo. The processes are performed in 3 hot cells used for target receipt, extraction, purification low specific activity (LSA) generator introduction, and packaging. A fourth hotcell is used for waste processing. The hot cell processing area takes up a footprint of 15.4 m 2 with the total footprint of the facility, including space for administrative offices, non-rad labs, quality assurance, and radiation buffer areas set at 763 m 2 . Waste is produced at a weekly rate of 257.8 g low activity solid waste and 8032.7 mL of low activity liquid waste, 8032 mL of which is water. This baseline hypothetical facility for production of medical isotopes via activation was then compared and contrasted to the hypothetical facility for production of medical isotopes via fission products to show the differences in approach for the two production modes. The two production modes had several highlighted differences including the overall facility and hot cell layout, the type and amount of waste produced by the respective facilities, and economic factors impacting production mode. Finally, a decision tree for which production mode might be more beneficial for an entrant into medical isotope production was developed based on the differences examined and the desired output of medical isotopes desired by the entrant.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2022

Latest results from the CUORE experiment

The CUORE experiment is searching for the neutrinoless double β decay of the 130Te using cryogenic calorimeters. The CUORE detector consists of 988 TeO2 crystals packed in 19 towers and placed in a cryogenic facility with a base temperature of 10 mK. Crystals are enriched in the isotope 130Te which is the candidate for the neutrinoless double β decay. It is taking data since 2017 at the Laboratori Nazionali del Gran Sasso in Italy. Such a long operation of a bolometric experiment in stable condition has no precedent: by reaching 1 tonne-year of exposure CUORE set a fundamental milestone for any future experiment using this technology. The CUORE collaboration investigated the neutrinoless double β decay of 130Te exploiting the updated 1 tonne-year of statistics, setting a limit of 2.2 × 1025 yr at the 90% of credibility interval on the half-life, with a median sensitivity of 2.8 × 1025 yr.

Adams, DQ↗