Longitudinal and Hall Transport in Amorphous InGaZnO4 Films Prepared by rf Sputtering Method

• Published in: physica status solidi (b) Vol. 254; no. 11
• Main Authors: Zhang, Hui, Xie, Xin‐Jian, Zhang, Xing‐Hua, Liu, Xin‐Dian, Li, Zhi‐Qing
• Format: Journal Article
• Language: English
• Published: 01.11.2017
• Subjects: electronic transport; electron–electron interaction; mesoscopic systems; transparent conducting oxides
• ISSN: 0370-1972; 1521-3951
• DOI: 10.1002/pssb.201700133

We systematically investigated the temperature behaviors of the electrical conductivity and Hall coefficient of two series of amorphous indium gallium zinc oxides (a‐IGZO) films prepared by rf sputtering method. The two series of films are ∼700 and ∼25 nm thick, respectively. For each film, the conductivity increases with decreasing temperature from 300 K down to Tmax, where Tmax, ranging from ∼90 to ∼115 K for our films, is the temperature at which the conductivity reaches its maximum. Below Tmax, the conductivity decreases with decreasing temperature. Both the conductivity and Hall coefficient vary linearly with lnT at low temperature regime. The lnT behaviors of conductivity and Hall coefficient cannot be explained by the traditional electron–electron interaction theory, but can be quantitatively described by the current electron‐electron theory due to the presence of granularity. Combining with the scanning electron microscopy images of the films, we propose that the boundaries between the neighboring a‐IGZO particles could make the film inhomogeneous and play an important role in the electron transport processes. For the amorphous indium gallium zinc oxide films deposited by rf sputtering method, it is found that both the conductivity and Hall coefficient vary linearly with lnT at low temperature regime, which does not depend on the thickness of the film. The phenomena can be well described by the current electron–electron Coulomb interaction theories in the presence of granularity.