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Weakening of excitonic screening effects in TixZn1-xO thin films
Nurfani E.a, Satrya C.D.a, Abdurrahman I.a, Sutjahja I.M.a, Winata T.a, Takase K., Rusydi A.c, Darma Y.a
a Physics of Electronic Material Research Division, Department of Physics, Institut Teknologi Bandung, Bandung, 40132, Indonesia
b College of Science and Technology, Nihon University, Tokyo, 101-0062, Japan
c Singapore Synchrotron Light Source, National University of Singapore, Singapore, 117603, Singapore
[vc_row][vc_column][vc_row_inner][vc_column_inner][vc_separator css=”.vc_custom_1624529070653{padding-top: 30px !important;padding-bottom: 30px !important;}”][/vc_column_inner][/vc_row_inner][vc_row_inner layout=”boxed”][vc_column_inner width=”3/4″ css=”.vc_custom_1624695412187{border-right-width: 1px !important;border-right-color: #dddddd !important;border-right-style: solid !important;border-radius: 1px !important;}”][vc_empty_space][megatron_heading title=”Abstract” size=”size-sm” text_align=”text-left”][vc_column_text]© 2017 Elsevier B.V.Excitonic transitions of TixZn1-xO thin films have been studied using spectroscopic ellipsometry in the photon energy range of 0.5–6.5 eV. ZnO-based thin films were deposited on Si substrates by DC-unbalanced magnetron sputtering with Ti concentrations of 0, 1, and 3 at.%. By using a combination of Tauc-Lorentz, Drude, and Gaussian oscillators, the complex dielectric function and its derivatives were obtained and analyzed. In pure ZnO, the excitonic transitions were observed at ~ 3.35 eV through critical point analysis of the complex dielectric function. Mid-gap states, which acted as an electronic screening of excitons, were found in the photon energy region of 1.50–3.35 eV. Upon 1 at.% Ti doping, the amplitude of the mid-gap states decreased from 0.26 to 0.04 while the amplitude of excitonic transitions increased from 0.22 to 0.28, as compared to the pure ZnO. We explain such phenomena due to the weakening of excitonic screening effects. The results show that Ti plays an important role in the electronic structure and excitonic effects of ZnO.[/vc_column_text][vc_empty_space][vc_separator css=”.vc_custom_1624528584150{padding-top: 25px !important;padding-bottom: 25px !important;}”][vc_empty_space][megatron_heading title=”Author keywords” size=”size-sm” text_align=”text-left”][vc_column_text]Complex dielectric functions,Critical point analysis,Doped zinc oxides,Electronic screening,Excitonic transition,Photon energy regions,Screening effect,Unbalanced magnetron sputtering[/vc_column_text][vc_empty_space][vc_separator css=”.vc_custom_1624528584150{padding-top: 25px !important;padding-bottom: 25px !important;}”][vc_empty_space][megatron_heading title=”Indexed keywords” size=”size-sm” text_align=”text-left”][vc_column_text]Doped zinc oxide,Doping, thin film,Screening effects,Spectroscopic ellipsometry,Sputtering,Titanium[/vc_column_text][vc_empty_space][vc_separator css=”.vc_custom_1624528584150{padding-top: 25px !important;padding-bottom: 25px !important;}”][vc_empty_space][megatron_heading title=”Funding details” size=”size-sm” text_align=”text-left”][vc_column_text]This work was supported by the Ministry of Research, Technology, and Higher Education of Republic of Indonesia through the 1st Batch PMDSU research program ( 794i/I1.C01/PL/2016 ). This work also was partly supported by the Desentralisasi research program ( 585g/I1.C01/PL/2016 ) and Riset Unggulan Perguruan Tinggi 2017 ( 009/SP2H/LT/DRPM/IV/2017 ; LPPM.PN-7-57-2017 ) of Indonesian Government. AR acknowledged Singapore National Research Foundation under its Competitive Research Funding ( NRF-CRP 8-2011-06 ), MOE-AcRF Tier-2 ( MOE2015-T2-1-099 , MOE2015-T2-2-065 , and MOE2015-T2-2-147 ), NUS YIA, and FRC ( R-144-000-368-112 , R-144-000-346-112 , and R-144-000-364-112 ).[/vc_column_text][vc_empty_space][vc_separator css=”.vc_custom_1624528584150{padding-top: 25px !important;padding-bottom: 25px !important;}”][vc_empty_space][megatron_heading title=”DOI” size=”size-sm” text_align=”text-left”][vc_column_text]https://doi.org/10.1016/j.tsf.2017.11.015[/vc_column_text][/vc_column_inner][vc_column_inner width=”1/4″][vc_column_text]Widget Plumx[/vc_column_text][/vc_column_inner][/vc_row_inner][/vc_column][/vc_row][vc_row][vc_column][vc_separator css=”.vc_custom_1624528584150{padding-top: 25px !important;padding-bottom: 25px !important;}”][/vc_column][/vc_row]