Fig. 1. (a) Excitation-power-dependent I–V (PDIV) curves at 300 K and (b) magnified graph. Squares and circles denote ISC and VOC, respectively.

Fig. 2. (a) VOC and ISC at 300 K plotted as functions of optical excitation power, and (b) ISC−VOC and I–V curves at 300 K plotted on linear and semi-log scales.

Fig. 3. (a) PDIV curves at 15 K and (b) magnified graph. Squares and circles denote ISC and VOC, respectively.

Fig. 4. (a) VOC and ISC at 15 K plotted as functions of optical excitation power, and (b) ISC−VOC and I–V curves at 15 K plotted on a semi-log scale.

Fig. 5. Normalized photoluminescence (PL) and electroluminescence (EL) spectra measured at (a) 80 mW, 10.1 mA (2.78 V), and 2.63 V (1.9 mA) at an operating temperature of 300 K and (b) 80 mW, 50 mA (4.23 V), and 1.9 mA (3.89 V) at 15 K, respectively.

Fig. 6. Schematic illustration of the band diagram including the proposed carrier transport and accumulation mechanisms at (a) 300 K and (b) 15 K.

Fig. 7. (a) I versus Veff2 curves depending on excitation power at 15 K, where the data are fitted with a linear curve; and (b) α and I0 as functions of optical excitation power.

Fig. 8. ηo−e and ηo−o as functions of optical excitation power at (a) 300 K and (b) 15 K.

Fig. 9. (a) PDIV curves at 15 K and (b) its magnified graph. The graphs are plotted for the same optical excitation power in Fig. 1 (0 to 100 mW, step: 20 mW).

Fig. 10. Normalized PL spectrum measured at 80 mW and EL spectra depending on the injected current (a) at 300 K and (b) 15 K, respectively.

Fig. 11. Normalized EL spectrum measured at 10.1 mA and PL spectra depending on the optical excitation power at 300 K.