Structural, optical, and electrical properties of V2O5 thin films: Nitrogen implantation and the role of different substrates
Bhanu Priya, Priya Jasrotia, Arun Kumar, Vinamrita Singh, Jehova Jire L. Hmar, Raj Kumar, P. K. Kulriya, Tanuj Kumar
Abstract
This report investigates the effect of substrate and nitrogen (16 keV N + ) ion implantation on the structural, morphological, compositional, and electrical properties of V 2 O 5 thin films which are grown by thermal evaporation on various substrates, including glass, Si, and sapphire (termed V 2 O 5 :Gl, V 2 O 5 :Si, and V 2 O 5 :Sp, respectively). Structural analysis showed the formation of the mixed ( α , and β-V 2 O 5 ) phases on all substrates; however, the β-V 2 O 5 phase is highly dominant in the V 2 O 5 :G and V 2 O 5 :Si samples. A deformation in the β-phase of V 2 O 5 thin film under ion implantation-induced strain results in a change of crystallite size. Irradiation suppresses XRD peaks in relative intensities, indicating partial amorphization of the film with defect formation. Microstructural analysis confirmed the formation of uniform-sized nanorods for V 2 O 5 :Si, whereas isolated crystallites were formed for other types of substrates. Thermal conductivity may influence the size and shapes of V 2 O 5 crystallite forms on different surfaces. Silicon absorbs heat more effectively than sapphire or glass, resulting in nanorod formation. A decrease in optical bandgap and electrical conduction has been observed due to increased oxygen vacancies, induced electron scattering, and trapping centres on N + implantation. The present study thus offers the unique advantage of simultaneous reduction in optical band-gap and conductance of V 2 O 5 thin films, which is important for optoelectronic applications.