Observation of low resistivity and high mobility in Ga doped ZnO thin films grown by buffer assisted pulsed laser deposition

• Ga doped ZnO thin films were grown using buffer assisted pulsed laser deposition.
• Lowest resistivity ∼5.1 × 10−5 Ω cm with a mobility of ∼41.9 cm2/V s was observed.
• Buffer assisted growth methodology maintains relatively good crystalline quality.
• This plays a key role in decreasing the resistivity of to the aforementioned value.
• This resistivity value, to the best of our knowledge is the lowest so far in ZnO.

We have grown Ga doped ZnO (GZO) thin films at moderate temperatures with Ga concentrations in the range varying from 0.25 to 3 at.% on sapphire substrates using buffer assisted pulsed laser deposition. Room temperature resistivity measured was ∼5.1 × 10−5 Ω cm with a electron mobility of ∼41.9 cm2/V s for an optimum Ga concentration of ∼0.75 at.% in the GZO films. Buffer assisted growth methodology maintains relatively good crystalline quality of the GZO thin films, thereby improving the electron mobility even at high dopant concentrations. This plays a key role in decreasing the resistivity of GZO films to the aforementioned value, which to the best of our knowledge is the lowest so far. These highly conducting GZO thin films with good mobility are potential candidates for transparent conducting oxide (TCO) applications in various optoelectronic devices.