Controlling the Electrical Properties of Undoped and Ta‐Doped TiO2 Polycrystalline Films via Ultra‐Fast‐Annealing Treatments. (7th January 2016)

• Record Type: Journal Article
• Authors: Mazzolini, Piero; Acartürk, Tolga; Chrastina, Daniel; Starke, Ulrich; Casari, Carlo Spartaco; Gregori, Giuliano; Bassi, Andrea Li
• Is Part Of: Advanced Electronic Materials. Volume 2:Number 3(2016)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2016-01-07
• Subjects: anatase -- defect chemistry -- perovskite‐based solar cells -- pulsed laser deposition -- transparent conducting oxides; Materials -- Electric properties -- Periodicals; Materials science -- Periodicals; Magnetic materials -- Periodicals; Electronic apparatus and appliances -- Periodicals; 537
• DOI: 10.1002/aelm.201500316
• Languages: English
• ISSNs: 2199-160X

Abstract

Abstract : A study on the crystallization process of undoped and Ta‐doped TiO2 amorphous thin films is presented. In particular, the effect of ultra‐fast‐annealing treatments in environments characterized by different oxygen concentrations is investigated via in situ resistance measurements. The accurate examination of the key parameters involved in this process allows us to reduce the time needed to obtain highly conducting and transparent polycrystalline thin films (resistivity ≈ 6 × 10 −4 Ω cm, mean transmittance in the visible range ≈ 81%) to just 5 min (with respect to the 180 minutes required for a "standard" vacuum annealing treatment) in nitrogen atmosphere (20 ppm oxygen concentration) at ambient pressure. Experimental evidence of superficial oxygen incorporation in the thin films and its detrimental role for the conductivity are obtained by employing different concentrations of traceable 18 O isotopes during ultra‐fast annealing treatments. The results are discussed in view of the possible implementation of the ultra‐fast annealing process for TiO2 ‐based transparent conducting oxides as well as electron selective layers in solar cell devices; taking advantage of the high control of the ultra‐fast crystallization processes which has been achieved, these two functional layers are shown to be obtainable from the crystallization of a single homogeneous thin film. Abstract : An ultra‐fast crystallization process to fabricate transparent and conducting TiO2 and Ta‐doped TiO2 thin films in nitrogen atmosphere at ambient pressure is reported. In situ resistance measurements in controlled annealing atmospheres demonstrate the possibility to finely control their electrical properties in an extremely fast process highly appealing for new generation solar cell devices.