One of the most significant and enduring challenges facing high-power GaN-based light-emitting diodes (LEDs) is the efficiency droop,i.e.the decrease of luminescence efficiency with increasing driving current,which constitutes a fundamental obstacle for widespread applications of GaN-based solid-state fighting devices as high-brightness sources for illumination.For the c-plane growth InGaN/GaN multiple quantum well (MQW) structures,the spectral range of LEDs emission can be extended to a longer wavelength into green region by either incorporating more In atoms into InGaN alloy layers or increasing the QW layer thickness.Some research groups have studied the influence of structure parameter,such as In content or well layer thickness,on the efficiency droop.[1-3] However,the peak emission wavelength of LED would vary if these structure parameters are changed.