埋覆膠狀量子點之微碟共振腔的製作與光學量測

Abstract

在本論文中，我們使用二氧化矽/矽的材料系統成功的製作出被動微碟共振腔(passive microdisk microcavity)，我們再結合膠狀量子點(colloidal quantum dots)製作出主動發光共振腔元件。 我們所利用的膠狀量子點分成Ⅳ-Ⅵ族的硫化鉛量子點和Ⅱ-Ⅵ族硒化鎘/硫化鋅量子點兩部分，在硫化鉛量子點微碟共振腔方面，我們利用自然沉降量子點於被動微碟共振腔上，成功的在低溫78K觀察出迴音廊模態(WGMs)的現象。 另一方面為結合硒化鎘/硫化鋅(CdSe/ZnS)量子點部分，我們利用三明治(sandwich)結構的優勢使得量子點放光在共振腔裡的侷限性(confinement)更好，更容易形成迴音廊模態(WGMs)，我們已成功的在室溫下觀察到迴音廊模態(WGMs)，由於硒化鎘/硫化鋅量子點放光範圍位於可見光區域，我們可以直接由電荷耦合元件(CCD)上觀測迴音廊模態(WGMs)的現象。

In this thesis, a passive microdisk microcavity has been successfully fabricated using a silicon and silicon dioxide dual structure. Two types of colloidal Quantum Dots (QDs) were then deposited to form the active media for light emission. The quantum dots used are lead sulfide (PbS) of IV-VI group and cadmium selenide / zinc sulfide (CdSe/ZnS) of II-VI group. PbS QDs deposition was achieved by relaxation deposition onto microcavities through solvent evaporation. In such cavity, Whispering Gallery Mode (WGM) resonances were successfully observed at a temperature of 78 Kelvin. For CdSe quantum dots, better optical confinement was achieved with deposited CdSe quantum dots sandwiched by SiO2 layers for better WGM resonance support. As the CdSe quantum dots emit at visible wavelength, WGM observation was made possible by implementing a Charged Coupled Device (CCD) for mode detection.