| Summary: | 碩士 === 國立成功大學 === 光電科學與工程學系 === 100 === In this dissertation, the InGaN/sapphire-based devices were epitaxially grown on (0001) pattern sapphire substrates by the metal-organic chemical vapor deposition epitaxy reactor. There were seven different InGaN-based structure designs, including the structure A with bulk p-InGaN p-type region, the structure B with three-step graded p-InGaN p-type region, the structure C with GaN/InGaN superlattice absorption layers, structure D with AlGaN/InGaN superlattice absorption layers, structure E with AlGaN/InGaN superlattice absorption layers and the thickness is 3nm/2.5nm, structure F is AlGaN/InGaN superlattice based device with 30nm p-InGaN insertion layer and structure G is AlGaN/InGaN superlattice based device with three 10nm graded p-InGaN insertion layers. These seven devices were fabricated and their properties applied on LED and solar cell were expounded.
The experiments were divided into four topics. The first topic is the comparison between structure A and B in order to discuss the influence of possible formation of 2DHG induced by graded p-InGaN. The results showed lower Rs and slightly higher output power in structure B. The second topic is the comparison between structure C and D to discuss the polarization effect. The JSC and VOC decreased and the RS increased markedly in structure D, thus the lower efficiency. The third topic is the comparison between structure A and C to observe the influence of different barrier thickness in absorption layers. In structure C, the RS were much reduced and the JSC and FF were increased and consequentially enhanced the efficiency for 20.6%. The fourth topic is the comparison between structure E, F and G. The structure F and G with p-InGaN insertion layers showed pronounced increase in output power with 42.6% enhancement, due to better carrier injection efficiency.
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