Thermionic Emission of Atomic Layer Deposited MoO3/Si UV Photodetectors

Mohamed A Basyooni; A E H Gaballah; Mohammed Tihtih; Issam Derkaoui; Shrouk E Zaki; Yasin Ramazan Eker; Şule Ateş

doi:10.3390/ma16072766

Thermionic Emission of Atomic Layer Deposited MoO₃/Si UV Photodetectors

Materials (Basel). 2023 Mar 30;16(7):2766. doi: 10.3390/ma16072766.

Authors

Mohamed A Basyooni^{1

2

3}, A E H Gaballah⁴, Mohammed Tihtih⁵, Issam Derkaoui⁶, Shrouk E Zaki^{1

7}, Yasin Ramazan Eker^{2

8}, Şule Ateş⁹

Affiliations

¹ Department of Nanotechnology and Advanced Materials, Graduate School of Applied and Natural Science, Selçuk University, Konya 42030, Turkey.
² Science and Technology Research and Application Center (BITAM), Necmettin Erbakan University, Konya 42090, Turkey.
³ Solar and Space Research Department, National Research Institute of Astronomy and Geophysics (NRIAG), Cairo 11421, Egypt.
⁴ Photometry and Radiometry Division, National Institute of Standards (NIS), Tersa St, Al-Haram, Giza 12211, Egypt.
⁵ Institute of Ceramics and Polymer Engineering, University of Miskolc, H-3515 Miskolc, Hungary.
⁶ Laboratory of Solid-State Physics, Faculty of Sciences Dhar el Mahraz, University Sidi Mohammed Ben Abdellah, P.O. Box 1796, Atlas Fez 30000, Morocco.
⁷ Theoretical Physics Department, National Research Center, Dokki, Cairo 12622, Egypt.
⁸ Department of Metallurgy and Material Engineering, Faculty of Engineering and Architecture, Necmettin Erbakan University, Konya 42060, Turkey.
⁹ Department of Physics, Faculty of Science, Selçuk University, Konya 42075, Turkey.

Abstract

Ultrathin MoO₃ semiconductor nanostructures have garnered significant interest as a promising nanomaterial for transparent nano- and optoelectronics, owing to their exceptional reactivity. Due to the shortage of knowledge about the electronic and optoelectronic properties of MoO₃/n-Si via an ALD system of few nanometers, we utilized the preparation of an ultrathin MoO₃ film at temperatures of 100, 150, 200, and 250 °C. The effect of the depositing temperatures on using bis(tbutylimido)bis(dimethylamino)molybdenum (VI) as a molybdenum source for highly stable UV photodetectors were reported. The ON-OFF and the photodetector dynamic behaviors of these samples under different applied voltages of 0, 0.5, 1, 2, 3, 4, and 5 V were collected. This study shows that the ultrasmooth and homogenous films of less than a 0.30 nm roughness deposited at 200 °C were used efficiently for high-performance UV photodetector behaviors with a high sheet carrier concentration of 7.6 × 10¹⁰ cm^-2 and external quantum efficiency of 1.72 × 10¹¹. The electronic parameters were analyzed based on thermionic emission theory, where Cheung and Nord's methods were utilized to determine the photodetector electronic parameters, such as the ideality factor (n), barrier height (Φ₀), and series resistance (R_s). The n-factor values were higher in the low voltage region of the I-V diagram, potentially due to series resistance causing a voltage drop across the interfacial thin film and charge accumulation at the interface states between the MoO₃ and Si surfaces.

Keywords: MoO3; UV illuminations; electric and optoelectronics; thermionic emission; ultrathin films.

Grants and funding

I would like to express my sincere gratitude to the Scientific Research Projects Coordination (BAP) Unit at Selçuk University for their invaluable support of our project with identification number 22211012.