CdS/CdTe/CuxS solar cells with Mo, ZnO and ZnO: Al electrodes icon

CdS/CdTe/CuxS solar cells with Mo, ZnO and ZnO: Al electrodes




НазваCdS/CdTe/CuxS solar cells with Mo, ZnO and ZnO: Al electrodes
Дата30.06.2013
Розмір13.2 Kb.
ТипДокументи

УДК 535.016



CdS/CdTe/CuxS solar cells with Mo, ZnO and ZnO:Al electrodes


T.V. Semikina1, S.V. Mamykin1, M. Godlewski2, G. Luka2, R. Pietruszka2, K. Kopalko2, T. A. Krajewski2, S. Gierałtowska2, L. Wachnicki2, L. N. Shmyryeva3

1 V. Lashkarev Institute of semiconductor physics NAS of Ukraine, Kiev, Ukraine

tanyasemikina@gmail.com

2 Institute of Physics Polish Academy of Sciences, Warsaw, Poland

godlew@ifpan.edu.pl

3National Technical University of Ukraine “KPI”, Kiev, Ukraine


In present work we study the photoelectrical characteristics of CdS/CdTe/CuxS solar cells deposited on different conductive materials that are used as an ohmic contact to CdS, namely Mo, ZnO and ZnO:Al. In our work we use atomic deposition method (ALD) to deposit metallic ZnO and ZnO:Al films. The ALD is modern nanotechnological method that allows deposition of very uniform thin films on large substrates. In our case we deposited thin films of ZnO and ZnO:Al on quartz glass substrates and used them as transparent contacts in tested solar cells. These films are very uniform in thickness, show high transparency in visible light spectral region and metallic conductivity [1]. The development of solar cell technology on alternative transparent substrates is crucial for the future applications.

Transparent conductive thin films of ZnO and ZnO:Al were grown in the Savannah-100 ALD reactor (Cambridge NanoTech) from diethylzinc and water vapor as zinc and oxygen precursors, respectively. For doping with aluminum, trimethylaluminum was used. Introduction of aluminum causes the decrease of films resistivity. But even undoped films have very low resistivity, i.e. 4×10-3 Ωcm. This is due to native defects, mainly zinc interstitial which can act as very efficient donors in ZnO. The resistivity of the films is the lower for Al content of 3 at.%, and is 8×10-4 Ωcm.

Solar cells of CdS/CdTe/CuxS studied by us were prepared by quasi-closed sublimation method from CdS and CdTe powders. The technology of quasi-closed sublimation method for growth of II-VI material layers is described in [3]. This method allows deposition of polycrystalline thin and thick films. CdS/CdTe/CuxS structures are deposited on pyroceram covered by Mo, quartz glass with ZnO film, and ZnO:Al. The films of n-CdS and n-CdTe were grown during one technological cycle. The thickness of the CdS is equal to 0.2 μm, for CdTe correspondingly is 1.0 μm. Since both CdS and CdTe layers have the n-type conductivity we deposited the layer of p-CuxS for barrier formation. Degenerated semiconductor CuxS is also as an electrode to CdTe.

We concentrated on the search for the best material choice (Mo, ZnO, ZnO:Al) of the bottom electrode and technological parameters deposition studying for preparing of high conductive ZnO and ZnO:Al films. Mo films were deposited on pyroceram substrates by magnetron sputtering using PVD 75 (Kurt J. Lesker) system. Theoretically molybdenum contact should be ohmic for n-CdS because of equal values of work functions Φ = 4.8 eV. In the case of ZnO and ZnO:Al we have some difference in work functions (ΦZnO = 4.3 eV, ΦZnO:Al = 4.53 eV) in comparison with CdS, but the contacts should be also ohmic [2].

The dark and illuminated current-voltage (I-V) characteristics of solar cells are measured under two illumination powers of 0.013 and 0.136 W/cm2 (incandescent lamp and halogen bulb respectively) and analyzed. The calculated efficiency of the best prepared solar cells is 1.89 % for samples on ZnO (short circuit current Isc=0.249 mA, open circuit voltage Uoc=0.3695 V, fill factor FF=0.267). We observed that structure of solar cells deposited on ZnO and ZnO:Al show the better I-V characteristics in comparison with solar cells with Mo contact. The exchange of Mo contact by ZnO leads to current increasing by a factor of three, for case of ZnO:Al the current increased by a factor of four under U=-0.5 V. The observed difference in photo current can be explained by distinctive properties of Mo and ZnO structures and quality of interfaces between CdS and conductive materials. The films of ZnO and ZnO:Al deposited by ALD method have polycrystalline structure, are very dense with root means square less than 2 nm. Most likely the interface of CdS/ZnO and CdS/ZnO:Al has lower density of surface traps in comparison with CdS/Mo resulting in the observed increase of the current.

Relatively low values of efficiency relates to the fact that the technological procedures are still not optimized. We omitted several operations of chemical and thermal treatments of CdS and CdTe layers that typically are applied for such type of solar cells. For example, the chloride etching was not applied. Another reason is the fact that the new structure n-CdS/n-CdTe/p-CuxS demands further optimization.


Conclusion

  1. We found the technological regimes for deposition of uniform, dense, transparent and conductive zinc oxide and ZnO:Al films by the ALD method.

  2. We demonstrate the advantageous use of thin films of ZnO and ZnO:Al as the electrodes to CdS. Their use leads to improved I-V characteristics and consequently to increased efficiency of n-CdS/n-CdTe/p-CuxS solar cells.


This work was partially supported by the European Union within the European Regional Development Fund, through the Innovative Economy grant (POIG.01.01.02-00-108/09).


REFERENCES

  1. Gieraltowska, S. Atomic layer deposition grown composite dielectric oxides and ZnO for transparent electronic applications / S. Gieraltowska, L. Wachinski, B.S. Witkowski, M. Godlewski, and E. Guziewicz // Thin Solid Films. – 2012. – Vol.520. – PP. 4694–4697.

  2. Jiang, X. Aluminum-doped zinc oxide films as transparent conductive electrode for organic light-emitting devices / X. Jiang, F. L. Wong, M. K. Fung, and S.T. Lee //Appl. Phys. Lett. – 2003. – Vol. 83. – PP.1875–1878.

  3. Ярошенко, Н. В. Получение тонкопленочных гетероструктур методом горячих стенок и исследование механизмов токопереноса / Н. В. Ярошенко, Т. В. Семикина, Ю. Н. Бобренко, W. Pashkovich, R. Minikaev, Л. Н. Шмырева, В. Н. Комащенко // Электроника и связь. – 2011. – №2. – С. 28–33.

Схожі:

CdS/CdTe/CuxS solar cells with Mo, ZnO and ZnO: Al electrodes iconFilm solar cells on cdS/CdTe base with different back contacts
Вах is established, that use of thin layers copper in a design of transparent contact results in decrease of reverse current saturation...
CdS/CdTe/CuxS solar cells with Mo, ZnO and ZnO: Al electrodes iconInvestigation of thin film solar cells on cdTe base
С during 25 min. CdCl2 treatment results in the significant recrystallization of CdTe layer. The average grain size of the film increases...
CdS/CdTe/CuxS solar cells with Mo, ZnO and ZnO: Al electrodes iconОсобенности кинетики тока изотермической деполяризации в варисторной керамике на основе znO

CdS/CdTe/CuxS solar cells with Mo, ZnO and ZnO: Al electrodes iconДокументи
1. /zno.docx
CdS/CdTe/CuxS solar cells with Mo, ZnO and ZnO: Al electrodes iconПоверхневі збудження плазмон-фононного типу в одновісних напівпровідниках zno та 6h-siC
Ніжинський державний університет імені Миколи Гоголя (16602, м. Ніжин, вул. Кропив’ян-ського, 2). E-mail
CdS/CdTe/CuxS solar cells with Mo, ZnO and ZnO: Al electrodes iconСтруктурні властивості плівок zno легованих sb
Одномірні наноструктури з оксиду цинку є перспективним матеріалом для створення лазерів І світловипромінювальних діодів в уф діапазоні,...
CdS/CdTe/CuxS solar cells with Mo, ZnO and ZnO: Al electrodes iconО. З. Діденко, канд хім наук Г. Р. Космамбетова
Показано, що збільшення розміру наночастинок ZnO від 7 до 10 нм призводить до зменшення їх активності незалежно від способу приготування...
CdS/CdTe/CuxS solar cells with Mo, ZnO and ZnO: Al electrodes iconУльтратонкі острівкові плівки золота на скляних підкладках
Нч [2] та його підсиленням в умовах збудження у активному шарі поверхневих плазмон-поляритонів. Таким чином, загальна поглинута потужність...
CdS/CdTe/CuxS solar cells with Mo, ZnO and ZnO: Al electrodes iconПункт прийому звернень абітурієнтів щодо участі у додатковій сесії зовнішнього оцінювання 2012 року знаходиться за адресою
М. Суми, вул. Римського-Корсакова, 5 Сумський обласний інститут післядипломної педагогічної освіти, навчально-методичний відділ зовнішнього...
CdS/CdTe/CuxS solar cells with Mo, ZnO and ZnO: Al electrodes iconМетод формування наноутворень cds
Отже, послідовно повторюючи такий мікросинтез слушну кількість разів, можна досягти необхідних розмірів кластерів CdS всередині матриці....
Додайте кнопку на своєму сайті:
Документи


База даних захищена авторським правом ©zavantag.com 2000-2013
При копіюванні матеріалу обов'язкове зазначення активного посилання відкритою для індексації.
звернутися до адміністрації
Документи