1. FIG. 4. Electroluminescence spectra of (a) Sample A (with shallow TQW), (b) Sample B (with shallow RQW), (c) Sample C (w/o. shallow QWs) at Various injection currents. (d) The magnitude of the blue-shift and the FWHM of the EL emission peak in the three samples as a function of injection current. 1.8 nm2.1 nm 5.1 nm

2.  The LED devices with shallow TQW gave a 0.35 V lower turn-on voltage and an 80% higher lighting efficiency than those of LEDs without shallow QWs.  The improvements were ascribed to the weakening effect of the inserted shallow TQW on the polarization field in the c-plane GaN-LEDs, leading to enhanced lighting efficiency and reduced efficiency-droop. Conclusion

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