Characterization of Thin-film Thermoelectric Micro-modules using Transient Harman ZT Measurement and Near-IR Thermoreflectance

2007 ◽  
Vol 1044 ◽  
Author(s):  
Rajeev Singh ◽  
James Christofferson ◽  
Zhixi Bian ◽  
Joachim Nurnus ◽  
Axel Schubert ◽  
...  
Keyword(s):  
Thin Film ◽  
Heat Load ◽  
Figure Of Merit ◽  
Near Infrared ◽  
Device Performance ◽  
Metal Contacts ◽  
Thermoelectric Figure ◽  
Near Ir ◽  
Harman Technique

AbstractWe characterize several thin film thermoelectric micro-modules composed of 20 µm-thick elements and designed for cooling applications to identify factors that may limit device performance. Thermoelectric figure-of-merit measurements using the transient Harman technique are compared with maximum cooling data under no heat load. Correlation between the two measurements depending on the location of the parasitic joule heating in the module is analyzed. Near-infrared thermoreflectance is used to examine temperature non-uniformity in the module. The temperature distribution on the metal contacts due to the Peltier and Joule effects is obtained non-destructively through the silicon substrate of an active module.

scholarly journals Characterization of conichalcite by SEM, FTIR, Raman and electronic reflectance spectroscopy

2005 ◽  
Vol 69 (2) ◽  
pp. 155-167 ◽  
Author(s):  
B. J. Reddy ◽  
R. L. Frost ◽  
W. N. Martens
Keyword(s):  
Near Infrared ◽  
Adsorbed Water ◽  
Reflectance Spectroscopy ◽  
Sem Images ◽  
X Ray ◽  
Near Ir ◽  
Ir Reflectance ◽  
Yavapai County ◽  
Ir Bands

AbstractThe mineral conichalcite from the western part of Bagdad mine, Bagdad, Eureka District, Yavapai County, Arizona, USA has been characterized by electronic, near-infrared (NIR), Raman and infrared (IR) spectroscopy. Scanning electron microscopy (SEM) images show that the mineral consists of bundles of fibres. Calculations based on the results of the energy dispersive X-ray analyses on a stoichiometric basis show the substitution of arsenate by 12 wt.% of phosphate in the mineral. Raman and IR bands are assigned in terms of the fundamental modes of AsO43− and PO43− molecules and are related to the mineral structure. Near-IR reflectance spectroscopy shows the presence of adsorbed water and hydroxyl units in the mineral. The Cu(II) coordination polyhedron in conichalcite can have at best pseudo-tetragonal geometry. The crystal field and tetragonal field parameters of the Cu(II) complex were calculated and found to agree well with the values reported for known tetragonal distortion octahedral complexes.

scholarly journals Anisometric Ln(III) Complexes with Efficient Near-IR Luminescence

Inorganics ◽  
2022 ◽  
Vol 10 (1) ◽  
pp. 9
Author(s):  
Andrey A. Knyazev ◽  
Aleksandr S. Krupin ◽  
Yuriy G. Galyametdinov
Keyword(s):  
Near Infrared ◽  
Emission Spectra ◽  
Structural Features ◽  
Infrared Range ◽  
Light Emitting ◽  
Near Ir ◽  
Re Elements ◽  
Stokes Shifts ◽  
Narrow Emission

Recent studies in development of near-infrared luminophores focus on overcoming their disadvantages such as low quantum efficiency, limited emission power, and broad emission spectra. Rare earth (RE) elements are promising compounds in this respect as they offer a unique set of optical properties that provide narrow emission spectra and large Stokes shifts. This work reports the results of synthesis and characterization of new anisometric complexes of lanthanide(III) tris(b-diketonates) and 1,10-phenanthroline. These complexes possess light emitting-properties in the near-infrared range. Due to their structural features, these complexes allow production of homogeneous films by spin coating. These films are transparent in the visible and near-infrared ranges (transmission up to 99%). This paper demonstrates advantages of Yb(III), Er(III), and Nd(III) complexes as potential components of highly efficient light-transforming NIR coatings.

Integration of InGaN-based Optoelectronics with Dissimilar Substrates by Wafer Bonding and Laser Lift-off

2001 ◽  
Vol 681 ◽  
Author(s):  
William S. Wong ◽  
Michael Kneissl ◽  
David W. Treat ◽  
Mark Teepe ◽  
Naoko Miyashita ◽  
...  
Keyword(s):  
Thin Film ◽  
Wafer Bonding ◽  
Device Performance ◽  
Light Emitting ◽  
Si Substrates ◽  
Substrate Removal ◽  
Transparent Substrate ◽  
Before And After ◽  
Lift Off

ABSTRACTInGaN-based optoelectronics have been integrated with dissimilar substrate materials using a novel thin-film laser lift-off process. By employing the LLO process with wafer-bonding techniques, InGaN-based light emitting diodes (LEDs) have been integrated with Si substrates, forming vertically structured LEDs. The LLO process has also been employed to integrate InGaN-based laser diodes (LDs) with Cu and diamond substrates. Separation of InGaN-based thin-film devices from their typical sapphire growth substrates is accomplished using a pulsed excimer laser in the ultraviolet regime incident through the transparent substrate. Characterization of the LEDs and LDs before and after the sapphire substrate removal revealed no measurable degradation in device performance.

Fabrication and Characterization of Annular-Shaped Piezoelectric Micromachined Ultrasonic Transducer Mounted with Pb(Zr,Ti)O3-Based Monocrystalline Thin Film

2021 ◽  
Author(s):  
Ziyi Liu ◽  
Shinya Yoshida ◽  
Shuji Tanaka
Keyword(s):  
Thin Film ◽  
Resonance Frequency ◽  
High Performance ◽  
Figure Of Merit ◽  
Ultrasonic Transducer ◽  
Device Fabrication ◽  
Static Displacement ◽  
Standard Design ◽  
Displacement Sensitivity

Abstract In this study, we propose an annular-shaped piezoelectric micromachined ultrasonic transducer (pMUT) based on a Pb(Zr,Ti)O3-based monocrystalline thin film. This pMUT is expected to increase the resonance frequency while maintaining displacement sensitivity, making it superior to an island-shaped pMUT, which is a conventional design. To demonstrate the validity of this assumption, annular- and island-shaped pMUTs with a 60-μm-diameter diaphragm were prototyped and characterized. As a result, the annular-shaped pMUT exhibited a resonance frequency of 11.9 MHz, a static displacement sensitivity of 2.35 nm/V and a transmitting figure-of-merit (FOM) of 28 nm∙MHz/V. On the other hand, the island-shaped pMUT exhibited a resonance frequency of 9.6 MHz and a static displacement of 2.5 nm/V and an FOM of 24 nm∙MHz/V. Therefore, the annular-shaped pMUT was experimentally demonstrated to provide a higher FOM compared to the island-shaped pMUT. In addition, the annular-shaped pMUT with the optimal dimensions is found to be able to keep a relatively large fabrication margin. This is an advantageous point for the practical device fabrication. We believe this design has a potential to become a standard design for high-performance pMUT devices.

Modified thermoelectric figure of merit estimated from enhanced mobility of [100] oriented beta-FeSi2 thin film

2007 ◽  
Vol 19 (4) ◽  
pp. 311-314 ◽  
Author(s):  
Hirofumi Kakemoto ◽  
Tohru Higuchi ◽  
Hajime Shibata ◽  
Satoshi Wada ◽  
Takaaki Tsurumi
Keyword(s):  
Thin Film ◽  
Figure Of Merit ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Figure ◽  
Enhanced Mobility

scholarly journals Measuring Device and Material ZT in a Thin-Film Si-Based Thermoelectric Microgenerator

Nanomaterials ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 653 ◽  
Author(s):  
Pablo Ferrando-Villalba ◽  
Antonio Pablo Pérez-Marín ◽  
Llibertat Abad ◽  
Gustavo Gonçalves Dalkiranis ◽  
Aitor F. Lopeandia ◽  
...  
Keyword(s):  
Thin Film ◽  
Thermal Conductivity ◽  
Figure Of Merit ◽  
Room Temperature ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Generators ◽  
Thermoelectric Figure ◽  
Measuring Device ◽  
Different Temperatures ◽  
Si Thin Film

Thermoelectricity (TE) is proving to be a promising way to harvest energy for small applications and to produce a new range of thermal sensors. Recently, several thermoelectric generators (TEGs) based on nanomaterials have been developed, outperforming the efficiencies of many previous bulk generators. Here, we presented the thermoelectric characterization at different temperatures (from 50 to 350 K) of the Si thin-film based on Phosphorous (n) and Boron (p) doped thermocouples that conform to a planar micro TEG. The thermocouples were defined through selective doping by ion implantation, using boron and phosphorous, on a 100 nm thin Si film. The thermal conductivity, the Seebeck coefficient, and the electrical resistivity of each Si thermocouple was experimentally determined using the in-built heater/sensor probes and the resulting values were refined with the aid of finite element modeling (FEM). The results showed a thermoelectric figure of merit for the Si thin films of z T = 0.0093, at room temperature, which was about 12% higher than the bulk Si. In addition, we tested the thermoelectric performance of the TEG by measuring its own figure of merit, yielding a result of ZT = 0.0046 at room temperature.

scholarly journals Integrable Near-Infrared Photodetectors Based on Hybrid Erbium/Silicon Junctions

Sensors ◽  
2018 ◽  
Vol 18 (11) ◽  
pp. 3755 ◽  
Author(s):  
Mariano Gioffré ◽  
Giuseppe Coppola ◽  
Mario Iodice ◽  
Maurizio Casalino
Keyword(s):  
Silicon Substrate ◽  
Room Temperature ◽  
Reverse Bias ◽  
Near Infrared ◽  
Optical Measurements ◽  
Device Performance ◽  
Light Sources ◽  
Monolithically Integrated ◽  
Fabrication And Characterization

This paper presents the design, fabrication, and characterization of Schottky erbium/silicon photodetectors working at 1.55 µm. These erbium/silicon junctions are carefully characterized using both electric and optical measurements at room temperature. A Schottky barrier ΦB of ~673 meV is extrapolated; the photodetectors show external responsivity of 0.55 mA/W at room temperature under an applied reverse bias of 8 V. In addition, the device performance is discussed in terms of normalized noise and noise-equivalent power. The proposed devices will pave the way towards the development of Er-based photodetectors and light sources to be monolithically integrated in the same silicon substrate, and both operating at 1.55 µm.

Thermal Characterization of Nanowire Array in a-Al2O3 Matrix

2001 ◽  
Vol 703 ◽  
Author(s):  
Diana-Andra Borca-Tasciuc ◽  
Gang Chen ◽  
Yu-Ming Lin ◽  
Oded Rabin ◽  
Mildred S. Dresselhaus ◽  
...  
Keyword(s):  
Thermal Diffusivity ◽  
Figure Of Merit ◽  
Average Length ◽  
Nanowire Array ◽  
Thermal Characterization ◽  
Thermoelectric Figure ◽  
Conduction Model ◽  
Effective Thermal Diffusivity ◽  
Nanowires Array

ABSTRACTThermal properties characterization of Bi nanowires is critical in order to validate the predicted enhancement of their thermoelectric figure-of-merit. In this paper we report the effective thermal diffusivity of Bi nanowires array embedded in a-Al2O3 (alumina) template. The composite material consists of 85% alumina and approximately 15% Bi nanowires with a diameter of 40 nm and an average length of 40 [.proportional]m. Measurements are performed along the nanowire axis. A thermal wave is produced at the front side of the sample and it is monitored at the backside through a fast thermoelectric effect. A one-dimensional heat conduction model is used to extract the thermal diffusivity.

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