Photoluminescence from InN nanorod arrays with a critical size

In this report, we investigated the rod size dependence of photoluminescence (PL) from vertically aligned indium nitride (InN) nanorod arrays grown on Si(111) substrates. Abnormal temperature dependence of the PL peak energy and the PL bandwidth was observed for InN nanorods with a critical diameter, which is of the same order of the surface electron accumulation layer (∼20 nm). Exceptionally large activation energy of the nanorods with the critical diameter implies that holes within these narrow nanorods need to surpass the band bending energy near the surface in order to recombine with electrons accumulated in the surface layer.