Weak localization and electron–electron interaction in GaN nanowalls

Abstract

We investigate the magneto-transport properties of GaN nanowalls grown by molecular-beam epitaxy on a sapphire substrate. The temperature dependent resistivity shows an upturn at T < 200 K due to localization behaviour at low temperatures. Magneto-conductance (MC) measurements at various temperatures from 3 K to 200 K were done in a magnetic field up to ±15 T applied parallel and perpendicular to the substrate. MC curves clearly show a sharp cusp like behaviour due to the weak-localization phenomenon and are fitted with Hikami–Larkin–Nagaoka equation (HLN). The phase coherence length deduced from the fit shows a decreasing behaviour with increasing temperature. The plot of phase coherence time (τφ) with T−1 shows a linear behaviour from 10 K down to 3 K denoting that the electron–electron interaction is the prime de-phase mechanism in the sample. The carrier density and mobility deduced from Hall measurements did not vary with temperatures which further substantiate that the interaction of the electrons in GaN nanowall plays a major role in the quantum correction.