Taiwan's National Cheng Kung University has developed a near-green LED using an indium gallium nitride growth process, which results in a peak external quantum efficiency of 48.6%. This process involves the growth conversion of indium nitride and gallium nitride at 2 second bursts. Many researchers are looking for ways to improve the efficacy of green LEDs. Currently, there is still no ideal material for producing efficient LEDs because the yellow-green gap exists between the red-visible spectra of red orange and indium gallium nitride in the arsenide/phosphide device. This LED material was grown on a patterned sapphire substrate from a Thomas Swan 19x2 inch densely coupled showerhead (CCS) MOCVD system. The owner of CCS technology is Ai Siqiang. The pattern of sapphire is a pyramid array having a diameter of 3.5 μm and a gap of 2 μm. The height of the pyramid is 1.3 μm. Figure 1 LED common architecture. The nitride semiconductor organometallic epitaxial sources are trimethylgallium, trimethylindium and trimethylaluminum (TMG, TMI, TMA) and ammonia ((NH3), nitrogen. The conversion of InN/GaN (Fig. 2) is The active illuminating region is performed by a multiple quantum well (MQW). The conversion loop contains 40 TMG and TMI two-second burst rings. The ammonia gas remains constant. The researchers also produced a standard TMG and TMI constant MQW during well growth. (LED I). Figure 2 Schematic diagram of source conversion sequences for LEDMQW growth (a) I and (b) II.
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