Faculty of Physics - University of Bucharest

UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS

Guest
2024-11-23 18:20

HOME CONFERENCES SEARCH LOGIN NEW USER IMAGES

Conference: Bucharest University Faculty of Physics 2023 Meeting

Section: Solid State Physics and Materials Science, Optics, Spectroscopy, Plasma and Lasers

Title:

Study of Optical and Electrical Properties of RF-Sputtered ZnSe/ZnTe Heterojunctions for UV detecting applications

Authors:

Ana-Maria PANAITESCU (1), Vlad-Andrei ANTOHE (1,2), Ștefan ANTOHE (1,3)

^*
Affiliation:

1) University of Bucharest, Faculty of Physics, R&D Center for Materials and Electronic & Optoelectronic Devices (MDEO), Atomiștilor Street 405, 077125 Măgurele, Ilfov, Romania.

2) Université catholique de Louvain (UCLouvain), Institute of Condensed Matter and Nanosciences (IMCN), Place Croix du Sud 1, B-1348 Louvain-la-Neuve, Belgium.

3) Academy of Romanian Scientists, Ilfov Street 3, 030167 Bucharest, Romania.

E-mail

anamaria.pam11@yahoo.ro

Keywords:

zinc selenide/zinc telluride (ZnSe/ZnTe) heterojunctions; radio-frequency magnetron sputtering (RF-MS); photoelectrical measurements; photodiodes; ultraviolet (UV) photodetectors.

Abstract:

Cadmium (Cd) – free photodiodes based on n-type Zinc Selenide / p-type Zinc Telluride (n-ZnSe/p-ZnTe) heterojunctions were prepared by Radio Frequency-Magnetron Sputtering (RF-MS) technique, and their detailed optical and electrical characterization was performed. Onto an optical glass substrate, 100 nm gold (Au) thin film was deposited by Thermal Vacuum Evaporation (TVE) representing the back-contact, followed by the successive RF-MS deposition of ZnTe, ZnSe, Zinc Oxide (ZnO) and Indium Tin Oxide (ITO) thin films, finally resulting in the Au/ZnTe/ZnSe/ZnO/ITO sub-micrometric “substrate”-type configuration. Next, the optical characterization by Ultraviolet-Visible (UV-VIS) spectroscopy was performed on the component thin films, and their optical band gap values were determined. The electrical measurements in the dark and under illumination at different light intensities were subsequently performed. The Current-Voltage (I-V) characteristics in the dark are nonlinear with a relatively high asymmetry, following the modified Shockley-Read equation. From their analysis, the series resistance, shunt resistance, the ideality factor and saturation current were determined with high accuracy. It is worth noting that the action spectrum of the structure is shifted to short wavelengths. A sensibility test for the 420-500 nm range was performed while changing the intensity of the incident light from 100 mW/cm2 down to 10 mW/cm2 and measuring the photocurrent. The obtained results provided sufficient information to consider the present sub-micrometric photodiodes based on n-ZnSe/p-ZnTe heterojunctions to be more suitable for the UV domain, demonstrating their potential for integration within UV photodetectors relying onto environmentally friendly materials.

References:

1. A. M. Panaitescu and V. A. Antohe, “Study of optical and electrical properties of RF-sputtered ZnSe/ZnTe heterojunctions for sensing applications”, Coatings 13(1), 208 (2023), doi: 10.3390/coatings13010208.

2. A. M. Panaitescu, I. Antohe, A. M. Răduță, S. Iftimie, Ș. Antohe, C. N. Mihăilescu and V. A. Antohe, “Morphological, Optical and Electrical Properties of RF-Sputtered Zinc Telluride Thin Films for Electronic and Optoelectronic Applications”, AIP Advances 12, 115013 (2022), doi: 10.1063/5.0116999.

3. A. M. Panaitescu, I. Antohe, C. Locovei, S. Iftimie, Ș. Antohe, L. Piraux, M. P. Suchea and V. A. Antohe, “Effect of the Cadmium Telluride Deposition Method on the Covering Degree of Electrodes Based on Copper Nanowire Arrays”, Applied Sciences 12(15), 7808 (2022), doi: 10.3390/app12157808.

4. O. Toma, V. A. Antohe, A. M. Panaitescu, S. Iftimie, A. M. Răduță, A. Radu, L. Ion and Ș. Antohe, “Effect of RF Power on the Physical Properties of Sputtered ZnSe Nanostructured Thin Films for Photovoltaic Applications”, Nanomaterials 11(11), 2841 (2021), doi: 10.3390/nano11112841.

5. D. Manica, V. A. Antohe, A. Moldovan, R. Pascu, S. Iftimie, L. Ion, M. P. Suchea and S. Antohe, “Thickness Effect on Some Physical Properties of RF Sputtered ZnTe Thin Films for Potential Photovoltaic Applications”, Nanomaterials 11(9), 2286 (2021), doi: 10.3390/nano11092286.

Acknowledgement:

The authors acknowledge infrastructure support from ‘R&D Center for Materials and Electronic & Optoelectronic Devices’ (MDEO) of the Faculty of Physics, University of Bucharest. The authors also acknowledge financial support from the ‘Physics Doctoral School’ of the University of Bucharest.