Production of SnO2/p-Si heterojunction structures by thermal evaporation, investigation of diode and photovoltaic characteristics of them

For the production of SnO2/p-Si heterojunction, p-Si (100) single crystal wafer with resistivity of ρ = 1-10 Ω.cm was used. Chemical cleaning of silicon (p-Si) was carried out according to the conventional procedure. For ohmic contact construction to the back surface of the crystal, Al (99.999%) metal, chemically cleaned, was evaporated using a vacuum coating unit.It was then annealed for 3 minutes in a nitrogen atmosphere at 580 oC by means of a quartz tube furnace. After the ohmic contact process, the tin oxide/p-Si heterojunction structures were produced by thermal evaporation in a vacuum coating unit using powdered tin oxide as obtained from the supplier (without further processing). For the optical examination of the tin oxide films in the produced heterojunction structures, the transmittance measurements vs the photon wavelength falling on the surface of the film in the visible light region were carried out using "Shimadzu 2450 UV-Vis spectrophotometer" device. For electrical characterization of the SnO2/p-Si heterojunctions, forward and reverse bias current-voltage (IV) measurements were carried out at room temperature and in dark using the "Keithley 6487 pikoammeter and voltage source" device. The characteristic parameters of the contacts such as ideality factor (n), barrier height (Φb), rectifying factor and series resistance (Rs) were determined.In addition, Norde function and Cheung functions were used to check the accuracy of the results obtained.In order to determine the photovoltaic parameters of the samples, I-V measurements were taken under AM1.5 (100 mW / cm2) illumination with the help of a solar simulator and parameters such as filling factor (FF) and conversion efficiency (η) were determined.In addition, Capacitance-Voltage (C-V), Capacitance-Frequency (C-f), Conductivity-Voltage (G-V), Conductivity-Frequency (G-f) measurements of the samples were also taken.