152lattice. Some authors argue that the reason for coexistence of the conductivity and transparency is related to the presence of shallow donor levels near the conduction band, formed by a large concentration of oxygen vacancies Vo [2]. However, other theoretical results predict that interstitial tin plays a more prominent role than Vo; the oxygen vacancies produce deep levels in the energy gap, but the outermost electrons of interstitial tin produce surface levels within the conduction band, generating a higher amount of charge carriers [1].The most reported TCO in literature is the Indium tin oxide ITO, but due to the high cost of Indium and the fact that it is ranked as 7.6 (being 9.5 the maximum) in the British Geological Survey risk list 2012 [10], in recent years research in alternative TCOs has been intensified [11]. SnO 2 is a good prototype for TCO, since it has a larger energy gap of 3.6 eV and is a material with a transparency above 80% in the visible range [1]. Thin oxide SnO 2 occurs in nature as the mineral cassiterite, which is normally associated with Power deposition influence on the electrical and optical properties of Sn 1-x O 2 Nb x thin films obtained by sputtering ABSTRACT: In a solid, the electrical conductivity and optical transparency seem to be two contradictory physical properties. Conductive materials are opaque, and transparent solids are electrical insulators. Combinations of these two physical properties in a material make it appropriate for application in many optoelectronic devices. The coincidence of these two properties has been mainly ascribed to point defects in the crystal lattice. In this work, we performed structural, electrical and optical characterization of thin films of one of the most promising transparent conductive oxides Sn 1-x O 2 Nb x . The films were grown on glass substrates by RF magnetron sputtering technique. As the deposition power was varied, it was found that the electrical conductivity of the films increased with increasing power deposition, and they showed a preferential growth in the (200) direction. All films exhibited optical transmittance in the visible range larger than 80%.
RESUMEN:En un sólido la buena conductividad eléctrica y la transparencia óptica parecen ser 2 propiedades contradictorias. Los materiales conductores son opacos, y los sólidos transparentes son aislantes eléctricos. La combinación de estas dos propiedades en un material lo hacen muy atractivo para una gran cantidad de aplicaciones optoelectrónicas. En este trabajo se realiza la caracterización estructural óptica y eléctrica de uno de los óxidos conductores transparentes más prometedores, el Sn 1-x O 2 Nb x . Las películas fueron crecidas sobre sustratos de vidrio por la técnica de sputtering RF. Al cambiar la potencia de deposición se halló que la conductividad eléctrica de las películas crecía al aumentar la potencia de deposición, lo cual coincidía con un crecimiento preferencial de las películas en el plano (200). Todas las películas muestran una transmitancia mayor al 80 % ...