以第一原理計算二維材料異質接面與鈣鈦礦結構甲胺鉛碘之光學吸收機制

First Principles Calculations on 2D Heterojunctions and Optical Transition Mechanisms of Perovskite MAPbI3

陳信安(Hsin-An Chen)

指導教授 ： 陳俊維

國立臺灣大學/工學院/材料科學與工程學研究所/博士(2016年)

https://doi.org/10.6342/NTU201601633

摘要

在此研究中，吾人首先以第一原理計算探討二為材料異質接面的性質。考慮的二維材料異質接面系統有包含石墨烯及其衍生物、二硫化鉬與六方晶系之氮化硼。這些二維材料彼此之間可以水平方式或垂直方式堆疊，且皆展現了特殊的性質以及應用。吾人將探討石墨烯基底的水平接面、二硫化鉬基底的水平接面與石墨烯/氮化硼/石墨烯的垂直接面。以水平接面來說，吾人主要關注其肖特基能障，亦即其能帶排列。對於垂直接面，其主要應用於穿隧接面元件，故吾人將關注能帶排列與其在外加電場下的行為。這些接面將可應用於各類奈米電子元件。

第二部份中，吾人將探討鈣鈦礦結構之甲胺鉛碘的光學吸收機制。此材料因其在可見光區有很強的吸收，近年來被廣泛運用於太陽能電池的吸光材料且得到很高的光電轉換效率。因此，研究其光學吸收機制將有助於釐清其關鍵之處。吾人將運用「能帶解析光學吸收密度」技術探討之。

關鍵字

石墨烯與其衍生物 ； 二硫化鉬 ； 能帶排列 ； 穿隧接面 ； 鈣鈦礦結構之甲胺鉛碘 ； 光學吸收機制 ； 能帶解析光學吸收密度

並列摘要

We have employed the first-principle calculations to investigate the interfaces of 2D materials in the first part. The considered 2D materials are graphene and its derivatives, MoS2 and hexagonal boron nitride. These 2D materials can be stacked horizontally or vertically. Both of them show special properties and would have some special applications. We research graphene-based horizontal junctions, MoS2-based horizontal junctions and graphene/h-BN/graphene vertical junctions. For horizontal junctions, we focus on Schottky barrier heights, i.e., band alignments. For vertical ones, they can be applied as tunneling junctions; hence band alignments under electric fields are important. This junction can be potentially used in the nanoelectronics.

Secondly, we investigate the optical transitions of perovskite MAPbI3. This material is widely used in the active layer of the solar cell device currently because of the strong absorption near visible-light region and the high power conversion efficiency of the device. Therefore, the optical transition near visible-light region would be the key factor. The band-resolved absorption density analysis is applied to investigate the optical transition mechanism.

並列關鍵字

graphene and its derivatives ； MoS2 ； band alignment ； tunneling junction ； perovskite MAPbI3 ； optical transition mechanism ； band-resolved absorption density analysis

參考文獻

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