IOSR Journal Of Applied Physics (IOSR-JAP) e-ISSN: 2278-4861.Volume 12, Issue 5 Ser. III (Sep. – Oct 2020), PP 57-61 www.Iosrjournals.Org DOI: 10.9790/4861-1205035761 www.iosrjournals.org 57 | Page Deposition and Bandgap Tailoring Of SnO Nano Thin Films by Coating with Zn, Cr and Dye of Tectona Grandis Leaf 1* C.N. Ukwu, 2 C.A. Elekwa, 3 P. E. Agbo, S.O. Okeke 4 1, Alex Ekwueme Federal University Ndufu Alike, P.M.B. 1010, Abakaliki, Ebonyi State 2,3 Ebonyi State University Abakaliki 4 Federal College of Education(Technical) Umunze Abstract Tin oxide (SnO) thin films are one of the most extremely studied due to its usefulness in UV-detector. SnO is known for wide bandgap of 3.6eV which makes it a good candidate for window layers in heterjunction solar cells. Transition metal chalcogenides (TMCs): Zinc (II) Sulphide (ZnS), Chromium (II) Sulphide (CrS), and dye- extracts exhibits unique properties such as high conversion efficiency, good absorption coefficient and good bandgap energy. These properties make their thin films versatile as coating materials. Spray pyrolysis Master Airbrush Brand-model G25, G255-SET and G266-SET have been used to deposit SnO, SnO:Zn-ion, SnO:Cr- ion, and SnO:dye of tectona grandis at 0.1M and 1% concentration respectively. The deposition was done at different substrate temperature of 50 o C, 100 o C, 150 o C and 200 o C. The dye used is extract from the leaves of tectona grandis. The effect of substrate temperature on the optical properties of the SnO (core) and SnO/TMCs (biphasic) films were examined and analysed vis-a-vis the bandgap. The result showed that the optical transmittance decreased with increase in substrate temperature for SnO (core). The bandgap energy for SnO is 2.00eV, 2.10eV, and 2.20eV at 50 o C, 100 o C, and 150 o C substrate temperature respectively. The energy band gap increased with substrate temperature indicating a blue shift. The result showed that for biphasic films under study the bandgap in all samples were in neighbourhood of 1.7eV-3.90eV for the different substrate temperature. All the energy band gap of the biphasic films is slightly lower than those of the core. It is also observed that the band gaps of the dye doped samples are lower: 1.55eV- 1.83eV than those of the Zn 2+ doped samples: 1.60eV – 2.20eV. The results reveals that the incorporation of the dye shifted the fundamental absorption edge of the un-doped SnO thin films thus providing tuning effect of the band gap for device applications. Key Words: Bandgap, Dopants (Zn 2+ & Cr 2- ), Dye of tectona grandis, and Substrate temperature --------------------------------------------------------------------------------------------------------------------------------------- Date of Submission: 15-10-2020 Date of Acceptance: 31-10-2020 --------------------------------------------------------------------------------------------------------------------------------------- I. Introduction Tin oxide (SnO) thin film has been one of the most extremely studied oxides because of its usefulness as a UV detector. As important group (II-VI) semiconductor with wide bandgap of 3.6eV, its thin film has versatile character. This film possesses wide applications in various technological fields, such as low electrical resistance with high optical transparency in the visible range, electrode materials in solar cells, flat display window layers, photo sensors among other applications including opto-electronic devices [8]. Many researchers had focused on the development of biphasic nanostructured materials on a nanometer scale, due to their device applications in several areas. According to Manoj, et al (2015), biphasic nanostructured composites are type of biphasic materials which have an inner structure of one material and outer structure of another material made of different components. These components have been the interest, as they can exhibit unique properties arising from the combination of the core and coating materials in their geometric or designed form. It is an alternative means of blending the best properties of the both for optimum enhancement. Biphasic nanostructure materials have been designed so that the coating material can improve the reactivity of the surface, thermal stability, or oxidation stability of the core structured material. TMC coating materials with different constituents show enhanced properties that differ from their corresponding non- functionalized uncoated bulk. [7]. The coating materials are important because they can influence the charge, functionality, and as well as improve the dispersive nature of core structured material. SnO has recently received much attention because of its unique properties, especially as an absorber layer in thin film solar cells. This is because the constituent elements tin and sulphur have emerged as simple, non-toxic and affordable materials for thin films solar cells since a decade [6, 9]. The compound has direct energy bandgap of 1.35eV for photovoltaic solar energy conversion [6].