Anomalous excitation-power-dependent photoluminescence of InGaAsN/GaAs T-shaped quantum wire

Abstract

The selected InGaAsN/GaAs T-shaped quantum wire (T-QWR) fabricated by metal organic vapor phase epitaxy has been investigated by microphotoluminescence (µ-PL) and excitation-power-dependent µ-PL. The optical characteristics of one-dimensional structure were taken at low-temperature (4 K) and room temperature (RT) to clarify the intersection of two familiar quantum wells (QWs) in the [001] and [110] directions, named QW1 and QW2, respectively. For the excitation-power-dependent measurement, the intensity of the excitation source was used in the range of 0.001I0 to I0. The result shows that all of emissions related to QW1 and QWR peaks have a nonsymmetric line shape as evidenced by the tailing on the lower-energy side. All peaks shift to higher-energy side (blueshift) with the increase of the excitation power intensity. The blueshift and the low-energy tailing of PL peaks are attributed to the alloying effect. However, the emission peak related to QWR region shows a larger blueshift rate than that of QW1 on increasing of the excitation power intensity. This is an anomalous characteristic for the low-dimensional structure, affected by the large fluctuation state in the QWR region. This fluctuation state is combined of both edges of QWs (QW1 and QW2).