Дослідження термометричного матеріалу HF1-хErxNiSn

Simple item page
dc.contributor.affiliationНаціональний університет “Львівська політехніка”uk_UA
dc.contributor.authorКрайовський, Володимир
dc.coverage.countryUAuk_UA
dc.coverage.placenameЛьвівuk_UA
dc.date.accessioned2018-03-16T07:55:57Z
dc.date.available2018-03-16T07:55:57Z
dc.date.issued2016
dc.description.abstractДосліджено енергетичні, кінетичні та магнітні характеристики термометричного матеріалу Hf1-xErxNiSn у діапазонах T = 80÷400 K, x=0÷0.10 за напруженості магнітного поля H £10 кГс. Показано, що характеристики Hf1-xErxNiSn чутливі до зміни температури і він може бути основою для виготовлення чутливих елементів термоперетворювачів. Исследованы энергетические, кинетические и магнитные характеристики термометрического материала Hf1-xErxNiSn в диапазонах: T = 80÷400 K, x=0÷0.10 при напряженности магнитного поля H £ 10 кГс. Показано, что характеристики Hf1-xErxNiSn чувствительны к изменениям температуры и он может быть основой для изготовления чувствительных элементов термопреобразователей. The electron energy state, magnetic and transport characteristics of of thermometric materials Hf1-xErxNiSn were investigated in the T = 80÷400 K temperature range and at charge carriers concentration from x=01÷0.10 and H £ 10 kGs. The material Hf1-xErxNiSn is sensitive to the temperature change and could be used as the basis for the sensitive thermoelectric devices. We investigated the crystal structure, electron density of states (DOS) and the kinetic and energy characteristics of n-HfNiSn heavily doped with the Er impurity. Samples were synthesized at the laboratory of the Institute of Physical Chemistry, Vienna University. The Hf1-xErxNiSn crystal-lattice periods were determined by X-ray analysis with the use of the Full-prof software. We employed a data array obtained by the powder method using a Guinier-Huber image plate system. The chemical and phase compositions of the samples were determined using a Ziess Supra 55VP scanning electron microscope and an EMPA energy dispersive X-ray analyzer. The electronic structure was calculated by the Korringa–Kohn–Rostoker (KKR) technique in the coherent potential approximation (CPA) and local density approximation (LDA), as well as the full-potential linearized plane wave (FP-LAPW) method within density functional theory (DFT). In the calculations, we used experimental values of the lattice constant on a k grid 10×10×10 in size and the Moruzzi–Janak–Williams exchange-correlation potential parametrization. The width of the contoured energy window was 16 eV. The number of energy values for DOS calculations was 1000. To predict the behavior of the Fermi level, band gap, and electrokinetic characteristics of n-HfNiSn doped with Eratoms, the electron density distribution (DOS) was calculated. The calculated results pretending to be adequate to experimental studies should account for complete information on the semiconductor’s crystalline structure. To obtain more accurate results, we calculated the DOS for almost all possible cases of the mutual substitution of atoms at sites of the HfNiSn unit cell. Shows the result most consistent with experimental data. It was found that the disordered structure (Hf1-xNix)NiSn, x = 0.01, of the HfNiSn compound is most probable. We note that the same result was obtained from structural studies of HfNiSn. The partial (to 1 at %) substitution of Hf atoms with Ni atoms generates donor-type structural defects in the crystal, and the Fermi level is in the band gap which becomes narrower. It was also found that the minimum in the dependence of variations in the DOS at the Fermi level (DOSF(x)) for the disordered structure (Hf1-xNix)NiSn of the HfNiSn compound corresponds to the (Hf0.99Ni0.01)NiSn composition. In this semiconductor model, the Fermi level is in the band gap which is εg ≈ 282 meV. The same question arises when analyzing the behavior of the dependences (x) and (x) in Hf1-xErxNiSn. For example, the (x) variation in the concentration range 0.02 ≤ x ≤ 0.10 shows that the modulation amplitude of the continuous energy bands of Hf1-xErxNiSn HDCSs increases. Indeed, the activation energies (x) increase from (x = 0.05) = 38.3 meV to (x) (x = 0.07) = 59.2 meV. As we already noted, such behavior is possible only when compensating electrons appear in the p-type semiconductor due to the ionization of donors whose appearance was not initially assumed. In Hf1-xErxNiSn samples, x > 0.05, the decrease in (x) indicates a decrease in the modulation amplitude of the continuous energy bands, which is possible only when the degree of compensation of Hf1-xErxNiSn decreases due to a decrease or termination of the generation of donor-type structural defects. Thus, the initial assumption that n-ZrNiSn doping with Er atoms by substituting Hf atoms is accompanied by the generation of only donor-type structural defects in the crystal does not allow consistent explanation of the behavior of the energy characteristics of Hf1-xErxNiSn HDCS. The variations in the activation energy of hopping conduction (x) and the modulation amplitude of the continuous energy bands (x) unambiguously prove the existence of a donor source in Hf1-xErxNiSn. Further, we will identify the possible mechanism for the appearance of donors. The series of studies on the crystalline structure, energy spectrum, and electro-kinetic parameters of the n-HfNiSn intermetallic semiconductor heavily doped with the Er impurity allowed determination of the variation in the degree of compensation of the semiconductor due to the generation of both structural defects of donor nature during the substitution of Hf atoms with Er atoms and defects of donor nature during the partial substitution of Ni sites with Snatoms. The n-HfNiSn crystalline structure is disordered, and the Hf site can be occupied by Ni to ~1 at %, which generates structural defects of donor nature in the semiconductor and explains the mechanism of its “a priori doping with donors”. The mechanism of the degree of compensation of the semiconductor as the result of the crystal structure transformation during doping, leading to the generation of structural defects of donor nature was established. The results of the electronic structure calculation are in agreement with experimental data and the Hf1-xErxNiSn semiconductor is a promising thermoelectric material. The results are discussed in the framework of the heavily doped and compensated semiconductor model by Shklovsky–Efros.uk_UA
dc.format.pages58–65
dc.identifier.citationКрайовський В. Дослідження термометричного матеріалу HF1-хErxNiSn / В. Крайовський // Вимірювальна техніка та метрологія : міжвідомчий науково-технічний збірник / Міністерство освіти і науки України ; відповідальний редактор Б. І. Стадник. – Львів : Видавництво Львівської політехніки, 2016. – Випуск 77. – С. 58–65. – Бібліографія: 5 назв.uk_UA
dc.identifier.urihttps://ena.lpnu.ua/handle/ntb/39799
dc.language.isoukuk_UA
dc.publisherВидавництво Львівської політехнікиuk_UA
dc.relation.references1. Romaka V. A., Rogl P., Romaka V. V., Kaczorowski D., Stadnyk Yu. V., Korzh R. O., Krayovskyy V. Ya. and Kovbasyuk T. M. Features of the Band Structure and Conduction Mechanisms of n-HfNiSn Semiconductor Heavily Lu-Doped // Semiconductors. – 2015. – Vol. 49. – Lviv Polytechnic National University Institutional Repository http://ena.lp.edu.ua Вимірювальна техніка та метрологія, № 77, 2016 р. 65 № 3. – Р. 290–297. 2. Ромака Л. П., Крайовський В. Я., Ромака В. В., Стадник Ю. В., Рогль П., Горинь А. М. Дослідження особливостей кристалічної та елект- ронної структур напівпровідникового твердого розчину Hf1-xTmxNiSn // Фізика і хімія твердого тіла. – 2016. – Т. 17. – № 2. – С. 212–221. 3. Ромака В. А., Рогль П., Стадник Ю. В., Ромака Л. П., Качаровський Д., Крайовський В. Я., Лах О. І. Дослідження структурних, енергетичних та кінетичних характеристик тер- моелектричного матеріалу Hf1-хYxNiSn // Термо- електрика. – 2015. – № 4. – С. 30–38. 4. Ромака В. А., Ромака В. В., Стадник Ю. В. Інтерметалічні напів- провідники: властивості та застосування. – Львів: Вид-во Львівської політехніки, 2011. – 488 с. 5. Romaka V. V., Rogl P., Romaka L., Stadnyk Yu., Grytsiv A., Lakh O., Krayovsky V. Peculiarites of Structural disorder in Zr- and Hf- Containing Heusler and Half-heusler Stannides // Intermetallics. – 2013. – Vol. 35. – P. 45–52.uk_UA
dc.subjectелектронна структураuk_UA
dc.subjectелектроопірuk_UA
dc.subjectкоефіцієнт термо-ЕРСuk_UA
dc.subjectэлектронная структураuk_UA
dc.subjectэлектросопротивлениеuk_UA
dc.subjectкоэффициент термо-ЭДСuk_UA
dc.subjectelectronic structureuk_UA
dc.subjectresistivityuk_UA
dc.subjectthermo-power coefficientuk_UA
dc.subject.udc537.311.322uk_UA
dc.titleДослідження термометричного матеріалу HF1-хErxNiSnuk_UA
dc.typeArticleuk_UA

Files

Original bundle
Now showing 1 - 1 of 1
No Thumbnail Available
Name:
vyp_77_Vymir-tech-58-65.pdf
Size:
549.63 KB
Format:
Adobe Portable Document Format
Description:
Download
License bundle
Now showing 1 - 1 of 1
No Thumbnail Available
Name:
license.txt
Size:
2.99 KB
Format:
Item-specific license agreed upon to submission
Description:
Download

Collections

Вимірювальна техніка та метрологія. – 2016. – Випуск 77