Anomalous Current–Voltage Behavior in Al/TiO₂/n‐Si Structures

Abstract

The current–voltage (J–V) curves of Al/TiO2/n‐Si structures present an anomalous behavior where the current becomes constant for a reverse bias higher than ≈0.65 V. Here we analyze devices fabricated by spin‐coating of an organometallic precursor and subsequent annealing in an O2 atmosphere. The details of the current saturation phenomenon are interpreted as a consequence of the formation of a depletion region in Si, which limits the voltage drop in the film and truncates the current. The analysis is supported experimentally by capacitance–voltage and photoconductance measurements. It is also shown that the saturation current can be controlled by modifying the film's deposition conditions, changing the barrier for electron injection from Al to TiO2.

KNbO3photoelectrode for DSSC: a structural, optical and electrical approach

“…This process generates a transparent TiO 2 film with <50 nm thickness (estimated by transmittance) that avoids charge recombination between the electrolyte and conductive transparent oxide by preventing the direct contact between them and causing weak light absorbance. 31…”

“…This process generates a transparent TiO 2 film with <50 nm thickness (estimated by transmittance) that avoids charge recombination between the electrolyte and conductive transparent oxide by preventing the direct contact between them and causing weak light absorbance. 31 To deposit a KNbO 3 film on the TiO 2 blocking layer, the KNbO 3 paste was prepared with 50 mg of the synthesized KNbO 3 , 50 μL of ethylene glycol and 20 μL of Triton X-100. The dispersion was kept under ultrasonic agitation for 2 h and then mixed using a Vortex mixer until the required viscosity was achieved.…”

Low recombination rates and improving charge transfer as decisive conditions for high current densities and fill factors in ZnS complex systems

“…The photoelectrode was composed of a TiO 2 blocking layer (BL) based on titanium isopropoxide bis(acetylacetonate) (Sigma-Aldrich) diluted in isopropanol (0.3 mol) and deposited by spin-coating in an area of 1 cm 2 in two steps: (i) 1500 rpm for 15 s; (ii) 3000 rpm for 30 s, followed subsequently by thermal treatment at 125 1C for 10 min and annealing at 500 1C for 30 min, 57 on an FTO substrate (Sigma-Aldrich, 7 O sq À1 ). After this process, a thick film was deposited on the BL layer with a doctor blade using a paste obtained from dissolution and consecutive vortexing of 25 mg of material (ZnO/ZnS, ZnO) in 7.5 mL of TRITON X-100, 2.5 mL of ethylene glycol (EG), and 2.5 mL of ethanol.…”