As we reported earlier [1], thermoelectric detectors can be competitive as nondispersive energy resolving focal-plane instruments in X-ray/UV spectrum. The first generations of prototype devices demonstrated the viability of detector design and provided good agreement between theoretical expectations and experimental data. These devices exploited sensors made of gold with a small fraction of iron impurity. To get the projected high resolution one needs another type of material, namely, lanthanum-cerium hexaborides. We report on the first experimental tests of the feasibility of lanthanum-cerium films as sensor materials. Progress with thin films of these materials argues for the success of these thermoelectric detectors

Badalyantz, G. R.

Fritz, G. G.

Gulian, Armen

Harutyunyan, S. R.

Horwitz, J. S.

Kuzanyan, A. S.

Petrosyan, S. A.

Van Vechten, D.

Vartanyan, V. H.

Wood, K. S.

Wu, H.-D.

English

Chapman University Digital Commons

Chapman University Chapman University Digital Commons Mathematics, Physics, and Computer Science Faculty Articles and Research Science and Technology Faculty Articles and Research 3-8-2002 Sensor Development for Single-Photon Thermoelectric Detectors Armen Gulian Chapman University, gulian@chapman.edu K. S. Wood Naval Research Laboratory G. G. Fritz Naval Research Laboratory D. Van Vechten U.S. Office of Naval Research H.-D. Wu Naval Research Laboratory See next page for additional authors Follow this and additional works at: https://digitalcommons.chapman.edu/scs_articles  Part of the Condensed Matter Physics Commons, and the Other Physics Commons Recommended Citation Gulian A.M., Wood K.S., Fritz G.G., Van Vechten D., Wu H.-D., Horwitz J.S., Badalyantz G.R., Harutyunyan S.R., Vartanyan V.H., Petrosyan S.A., Kuzanyan A.S. Sensor development for single-photon thermoelectric detectors. AIP Conference Proceedings (LTD-9), 2002, vol. 605, pp. 31-34. https://doi.org/10.1063/1.1457588 This Conference Proceeding is brought to you for free and open access by the Science and Technology Faculty Articles and Research at Chapman University Digital Commons. It has been accepted for inclusion in Mathematics, Physics, and Computer Science Faculty Articles and Research by an authorized administrator of Chapman University Digital Commons. For more information, please contact laughtin@chapman.edu. Sensor Development for Single-Photon Thermoelectric Detectors Comments This article was originally published in AIP Conference Proceedings, volume 605, issue 1, in 2002. https://doi.org/10.1063/1.1457588 Copyright American Institute of Physics Authors Armen Gulian, K. S. Wood, G. G. Fritz, D. Van Vechten, H.-D. Wu, J. S. Horwitz, G. R. Badalyantz, S. R. Harutyunyan, V. H. Vartanyan, S. A. Petrosyan, and A. S. Kuzanyan This conference proceeding is available at Chapman University Digital Commons: https://digitalcommons.chapman.edu/scs_articles/766 Sensor development for single-photon thermoelectric detectorsA. M. Gulian, K. S. Wood, G. G. Fritz, D. Van Vechten, H.-D. Wu et al.  Citation: AIP Conf. Proc. 605, 31 (2002); doi: 10.1063/1.1457588 View online: http://dx.doi.org/10.1063/1.1457588 View Table of Contents: http://proceedings.aip.org/dbt/dbt.jsp?KEY=APCPCS&Volume=605&Issue=1 Published by the AIP Publishing LLC.  Additional information on AIP Conf. Proc.Journal Homepage: http://proceedings.aip.org/ Journal Information: http://proceedings.aip.org/about/about_the_proceedings Top downloads: http://proceedings.aip.org/dbt/most_downloaded.jsp?KEY=APCPCS Information for Authors: http://proceedings.aip.org/authors/information_for_authors Downloaded 30 Aug 2013 to 128.118.88.48. This article is copyrighted as indicated in the abstract. Reuse of AIP content is subject to the terms at: http://proceedings.aip.org/about/rights_permissionsSensor Development For Single-PhotonThermoelectric DetectorsA. M. Gulian1, K. S. Wood2, G. G. Fritz3, D. Van Vechten4, H.-D. Wu5,J, S. Horwitz2, G. R. Badalyantz6, S. R. Harutyunyan6, V. H. Vartanyan6,S. A. Petrosyan6, A. S. Kuzanyan61 Physics Art Frentiers/NRL, Washington, DC 20375, USA2NRL, Washington, DC 20375, USA3PRAXIS/NRL, Washington, DC 20375, USA4ONR, Arlington, VA 22217, USA5SFA/NRL, Washington, DC 20375, USAPRI, National Academy of Sciences, Ashtarak-2, 378410, ArmeniaAbstract. As we reported earlier [1], thermoelectric detectors can be competitive as non-dispersive energy resolving focal-plane instruments in X-ray/UV spectrum. The first generationsof prototype devices demonstrated the viability of detector design and provided good agreementbetween theoretical expectations and experimental data. These devices exploited sensors madeof gold with a small fraction of iron impurity. To get the projected high resolution one needsanother type of material, namely, lanthanum-cerium hexaborides. We report on the firstexperimental tests of the feasibility of lanthanum-cerium films as sensor materials. Progress withthin films of these materials argues for the success of these thermoelectric detectors.1. INTRODUCTIONWhen a photon is absorbed in material its energy is converted to excitations in thematerial. The photon's energy quickly appears as temperature excess near theabsorption site. Measuring this excess is one way of determining what energy thephoton had. Because of an effect that has been well known since the early nineteenthcentury, — thermoelectricity — the temperature difference between the photonabsorption site and its surroundings will have associated with a measurable (transient)voltage difference and it is possible that this difference can be exploited for photoncharacterization. A priori, there is no way to be certain that it is not better than othermethods; one must investigate it.2. EXPERIMENTAL RESULTS WITH GOLD-IRON SENSORSFigure 1 shows the crucial portion of the device associated with the two absorbingpixels and the thermoelectric sensor connecting them. It also indicates the materialand geometrical parameters. In operation the device is cooled to temperatures belowIK and laser pulses are used to determine its response. The usual scheme forCP605, Low Temperature Detectors, edited by F. S. Porter et al.© 2002 American Institute of Physics 0-7354-0049-0/02/$ 19.0031Downloaded 30 Aug 2013 to 128.118.88.48. This article is copyrighted as indicated in the abstract. Reuse of AIP content is subject to the terms at: http://proceedings.aip.org/about/rights_permissions%& ̂ *&||1̂ ! KE?^I^M^^^E^EJ^^^-^^^fe^mlFIGURE 1. Experimental device (left) and its schematics (right).measurements is shown in Fig.2 (a). To assure that only one pixel is illuminated in thepulse a reflecting foil, as shown by Fig. 2(b) screens one half of the detector. Thin andnarrow superconducting leads (detectable in Fig.l) connect the two-pixel region of thedevice to the signal acquisition circuitry, schematically described in Fig. 3(a). Thetypical device output is shown in Fig. 3(b).Sample at 0.3KHe-3 cryostatUV-laserpulse(+IR and Greenoptions)splitterEnergy control(a) (b)FIGURE 2. (a) Experimental scheme for device testing, (b) Because of the large number of photons inthe pulse only half of the device was exposed to the radiation.Devices built using gold with controlled iron impurities were the natural choice for themodel validation phase. Fundamental characteristics of the output such as theamplitude, signal duration, signal/noise ratio agree well between the theory and theexperiment. The energy resolution obtained with gold/iron devices was about 500 eVat 6 keV energy deposited. In principle, it was possible to pursue more than an ordercryostat(a) (b)FIGURE 3. (a) Electronics circuit for signal acquisition, (b) Detector output (voltage pulse generatedby thermoelectric sensor element, ~100ns in duration, upper curve) in response to a very short laserpulse (~20ns in duration, bottom curve).32Downloaded 30 Aug 2013 to 128.118.88.48. This article is copyrighted as indicated in the abstract. Reuse of AIP content is subject to the terms at: http://proceedings.aip.org/about/rights_permissionsof magnitude higher resolution with this material, by adjusting the iron concentrationin gold, as well as the geometrical parameters of the sensor and material parameters ofthe absorber. However this is not a development path that would lead to the highestperformance devices. The model predicts spectral resolution to be [1]:= 2.35{2kBT2Cabs(l+Lo/S2}1/2, (1)where S is Seebeck's coefficient S for the sensor material. Other quantities in Eq. (1)are: Cabs - the absorber heat capacity, T - the operational temperature, LQ - the Lorenznumber. The detector is not optimized unless the values of S are higher than (or atleast close to) lOOjiV/K at operational temperatures. In the best case gold/iron materialcan have S about 10|LtV/K, which is not sufficient. Extensive search in the literaturerevealed another Kondo-metal, Lanthanum Hexaboride with partial (1%) substitutionof Lanthanum by Cerium (Fig. 4(a)). We investigated whether the properties of thismaterial agreed with assumptions made in our theoretical modeling, in particular, howclosely the Wiedemann-Franz relation (ke/a; see Ref. 1) is followed (Fig. 4(b)). Thesefigures argue strongly that the requirements have a chance to be met.3. KONDO-MECHANISM IN HEXABORIDE FILMSSince the basic constituent of this development is thermoelectric sensors, we havefocused our recent experimental efforts on the films of the candidate materialLao.99Ceo.oiB6 with best known properties for the detector application. As in Au(Fe)case, in this material, the high value of Seebeck coefficient is due to the Kondo-mechanism. For La(Ce)B6 the resistance of the bulk samples behaves as shown inFig.5, left. This is the simplest measurement one can perform to confirm the presenceof the Kondo mechanism and check the quality of the film. In films, there is typicallyhigher residual contribution (temperature independent background). The100-i80-60-40-20--20--40-O La Ce B0.99dOocP0°°>| X Au+10ppmFeoonf> %0oo*x x x xxxx>$^» (optimized composition) |HCJTemperature, K(a)Temperature, K(b)FIGURE 4. (a) Seebeck coefficients of Lao.99Ce0.oiB6 (Ref.2) and optimized Au(Fe) (Ref.3). Thehexaboride is obviously preferable, (b) Below 3K the Wiedemann-Franz law holds not only in LaB6,but also in CeB6 [4]. No Lorenz number data exist yet for Lao.99Ceo.oiB6.33Downloaded 30 Aug 2013 to 128.118.88.48. This article is copyrighted as indicated in the abstract. Reuse of AIP content is subject to the terms at: http://proceedings.aip.org/about/rights_permissions0.6 :0.40.210 20 30 40Temperature, K50FIGURE 5. Kondo-resistivity in bulk La(Ce) B6 samples should have a minimum at about T=20K(Ref.5). This figure documents our experimental data for Ijum thick La0.99Ce0.oiB6 films (the constantbackground subtracted, see text).greater the purity and crystallinity of the sample, the lower the background. We usede-beam deposition system to deposit La0.99Ce0.oiB6 onto heated (up to 950C) substratesfrom stoicheometric targets (99.9% purity). Multiple technological improvements veryrecently yielded films that are only a factor of two higher in room-temperatureresistance than bulk samples described in the literature. We are now at the stage ofmeasurement of these samples at low temperatures. Figures 5 and 6 are the firstdemonstration anywhere that the Kondo effect is seen in thin films of hexaborides.This is an interesting result in materials science for thermoelectrics, but it is crucialand enormously encouraging for our detector development. Seebeck coefficient in thinfilms will be measured in the next step.10 100Temperature, KFIGURE 6. Residual resistivity and Kondo behavior of recently deposited and tested films. The valuefor the bulk material is shown for comparison. Thin films are rapidly approaching the bulk limit as ourtechnique improves.REFERENCES1. Gulian A., Wood K., Fritz G., Gyulamiryan A., Nikoghosyan V., Giordano N., Jacobs T., and Van Vechten D.,NIMA 444, 232-236 (2000).2. Bickers N. E., Cox D. L., and Wilkins J. W., Phys.Rev. Lett., 54, 230-233 (1985).3. MacDonald D. K. C., Pearson W. B., and Templeton I. M., Proc. Roy. Soc. A 266, 161-184 (1962).4. Peysson Y., Ayache C., Sake B., Kunii S., and Kasuya T., J. of Magnetism and Magn. Mat., 59, 33-40 (1986).5. Samwer K. and Winzer K., Z. Physik B, 25, 269-274 (1976).34Downloaded 30 Aug 2013 to 128.118.88.48. This article is copyrighted as indicated in the abstract. Reuse of AIP content is subject to the terms at: http://proceedings.aip.org/about/rights_permissions

Sensor Development for Single-Photon Thermoelectric Detectors

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Sensor Development for Single-Photon Thermoelectric Detectors

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