Aomic scale structure control of InN and InGaN by immiscible nature in order to form a base for device applications

2018 Fiscal Year Final Research Report

• Project/Area Number: 15H03559
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Crystal engineering
• Research Institution: Ritsumeikan University
• Principal Investigator: Nanishi Yasushi 立命館大学, 理工学部, 授業担当講師 (40268157)
• Co-Investigator(Kenkyū-buntansha): 荒木 努 立命館大学, 理工学部, 教授 (20312126)
• Research Collaborator: AKASAKA Tetsuya ; YAMAGUCHI Tomohiro ; UEDONO Akira ; SUDA Jun
• Project Period (FY): 2015-04-01 – 2019-03-31
• Keywords: InN / InGaN / InAlN / 窒化物半導体 / 混晶組成 / MBE / 転位 / グラフィン

Outline of Final Research Achievements

InGaN alloys are currently used for blue LEDs. Material properties are degraded dramatically, however, when we increase In composition to fabricate green, red and infra-red LEDs. Growth of composition-controlled higher quality InGaN with nano-structure was investigated by using newly developed DERI process, taking advantage of immiscible nature of this material system. It was found that effect of dislocation can be suppressed by growing Ga-rich wider band-gap material surrounding dislocations. On the other hand, stress from the substrate due to lattice mismatch affects alloy composition at the interface. Insertion of graphene substantially improved the quality of InN due to stress decrease

Free Research Field

化合物半導体結晶成長およびデバイス

Academic Significance and Societal Importance of the Research Achievements

本研究の成果は社会的には、InGaN混晶の波長利用可能領域を、青・緑色領域から、さらに、赤、赤外領域まで拡張する上で、その指針を得たことにある。一方学術的意義は、非混和性の強いInGaN, InAlN混晶の組成は、結合力差による一方の原子の優先的な固相への取り込みに加え、基板結晶との格子定数差の違いによる組成引き込み効果も重要な役割を演じていることを明らかにしたことにある。ファンデルワールス力結合によるグラフィンを基板との界面に挟むより、組成決定に対する基板からの制約を軽減できることを示したことも大きな意義と考えている。