InP 양자점 합성 및 반응 메커니즘

국문 초록 (Abstract)

콜로이드 양자점은 입자 크기를 조절하여 밴드갭을 조절 할 수 있을 뿐만 아니라 용액공정이 가능하여 생산원가 경쟁력, 다양한 소자에 적용이 가능하며, 발광파장의 좁은 반치폭을 갖는 등 많은 장점이 있다. 그 중에서도 인듐포스파이드(InP) 양자점은 가시광선영역부터 근적외선 영역의 발광이 가능한 밴드갭을 갖고 있으며, 카드뮴 기반의 양자점 대비 인체 및 환경에 독성이 적어 차세대 발광소재로 주목 받고 있다.
이 논문에서는 InP 양자점의 문제점 중 하나인 입자 크기 균일도 문제를 다룬다. 인듐포스파이드 양자점에서 균일한 크기의 입자가 형성되지 못하는 원인을 파악하고, 핵 생성 및 성장이론(Nucleation and growth theory)에 기반하여 합성방법을 개선하였다. 방법은 간단히 (1) 전구체의 안정성 조절, (2) 슬로우 인젝션 방법을 적용한 InP 양자점 합성을 진행하였고, 그 결과 포커싱 성장(focusing growth)을 이루어 성장이 진행됨에 따라 입자의 균일도가 개선될 수 있었다. 결과적으로 제 1 흡수대(first absorption) 2.056 eV에서 반값반폭(Half width at half maximum) 0.097 eV로 매우 작은 값을 갖는 양자점을 합성 할 수 있었다.
이 새로운 합성방법은 모노머 공급 조절을 통해 포커싱 성장을 이룰 수 있음을 보여주었고, InP 외 다른 나노 입자에도 적용이 가능할 것으로 기대된다.

다국어 초록 (Multilingual Abstract)

Semiconductor quantum dots have several merits such as tunable band gap by adjusting size, cost effective colloidal synthesis, and narrow light emission spectrum. As one of the recently emerging materials, indium phosphide (InP) quantum dots(QDs) cover the emission range from visible to near infrared wavelength and they have less toxicity than cadmium based QDs.
This paper deals with problems related to the uniformity of InP size. Based on nucleation and growth theories, this paper explains why InP QD is less uniform than other materials. To solve these problems, we have approached these two directions to achieve size focus growth. 1) controlled the stability of single-source precursors. 2) We applied a new synthesis method called slow injection method. With this method, focus growth was achieved and a narrow half width at half maximum (HWHM, value : 0.097 eV) was obtained at the first absorption peak position of 2.056 eV. This means that control of the monomer feed rate can achieve focusing growth. I expect this method to be applied to other materials as well.

목차 (Table of Contents)

• Ⅰ. 서 론 ····················································································· 1
• 1. 양자점 소개······························································· 1
• 2. 엑시톤 보어반경과 양자제한효과 ·························3
• 3. 인듐 포스파이드(Indium phosphide, InP) 양자점
• ····················································································· 5
• Ⅱ. 단일소스 전구체의 안정성 조절······································· 13
• 1. 배경············································································ 13
• 2. 실험방법···································································· 16
• 3. 결과 및 고찰····························································· 20
• Ⅲ. 핵 생성 및 성장의 분리 – 슬로우 인젝션 방법·············· 28
• 1. 배경············································································· 28
• 2. 실험방법····································································· 29
• 3. 결과 및 고찰······························································ 33
• Ⅴ. 결 론······················································································ 38
• 참고문헌 ·············································································· 40