Emission Characteristics Based on Nanocolumn Photonic Crystal Effect of Orderly Arrayed InGaN/GaN Nanocolumns

In this paper, we discuss the emission characteristics based on the nanocolumn photonic crystal effect. The GaN nanocolumn arrays, at the top region of which InGaN/GaN MQWs were integrated, were optically pumped resulting in lasing oscillation, as shown in Fig. 2. Clear thresholds were observed in the light intensity vs. excitation density characteristics (see Fig.2 (c)). The lasing wavelength changed from 492.3 to 501.1 nm with increasing the column diameter (D) from 183 to 205 nm at the lattice constant (L) of 245 nm, as the result of the photonic band edge shift. Figure 3 shows the photonic band diagram of a nanocolumn system; note that the experimental lasing wavelength corresponded to the photonic band edge at Γ11. The normalized band edge wavelength L/λ is expressed as a function of the structural parameter of D/L 13) as shown in Fig. 4 (a), where the experimental lasing wavelength are plotted by circles.