Electrical properties of transparent and conducting Ga doped ZnO

Abstract

In this paper, we report on the metal-semiconductor transition behavior observed in transparent and conducting ZnO:Ga films grown by pulsed-laser deposition. The electrical resistivity measurements were carried out on ZnO films with varying Ga concentration in the temperature range of 14to300K. The electrical properties were correlated with film structure, and detailed structural characterization was performed using x-ray diffraction, transmission electron microscopy, and x-ray photoelectron spectroscopy. The room-temperature resistivity of these films was found to decrease with Ga concentration up to 5% Ga, and then increase. The lowest value of resistivity (1.4×10−4Ωcm) was found at 5% Ga. Temperature dependent resistivity measurements showed a metal-semiconductor transition, which is rationalized by localization of degenerate electrons. A linear variation of conductivity with T below the transition temperature suggests that the degenerate electrons are in a weak-localization regime. It was also found that the transition temperature is dependent on the Ga concentration and is related to the increase in disorder induced by dopant addition. The results of this research help to understand the additional effects of dopant addition on transport characteristics of transparent conducting oxides (TCOs) and are critical to further improvement and optimization of TCO properties.

Electrostatic tuning of Kondo effect in a rare-earth-doped wide-band-gap oxide

“…45 It is also noteworthy that a resistance upturn at low temperatures was also observed in ZnO thin films doped with nonmagnetic Ga ions. 46 But in that case, a linear variation of conductivity with √ T below the metal-insulator transition suggests that the degenerate electrons are in the weak localization regime. This further underscores the dispensable role of rare-earth Gd ions with f electrons in producing the Kondo effect in the ZnO host.…”

Effects of substrate temperature on the properties of heavy Ga-doped ZnO transparent conductive film by RF magnetron sputtering

“…TCOs with transmittance and resistivity values close to that of ITO have been widely researched in order to substitute ITO [1][2][3]. Among these TCOs, ZnO is the most favourable material for its wide band energy (3.37 eV), abundant resources and non-toxic [4,5].…”

Photoinduced Kondo effect inCeZn3P3

“…In carrier localization, the degree of disorder affects the position of T min , below which ρ starts to increase 40 . The tuning of carrier density by various illumination-power levels changes the degree of disorder, resulting in a shift of T min ; in fact, such a shift of T min under varying degrees of illumination has been previously reported in a semiconductor 41 .…”