- 學位論文
以分子束磊晶法成長硒化鎘量子點綠光發光二極體
CdSe quantum dots green light emitting diodes grown by molecular beam epitaxy
摘要
摘要 我們利用分子束磊晶法成長有無摻雜氯的硒化鎘量子點，並且以光激螢光實驗探討摻雜氯對硒化鎘量子點的影響。我們發現摻雜氯會令硒化鎘量子點在室溫下發光效率有大幅度的增強，我們認為這是由於摻雜而令導電帶有更多的電子，因此電子電洞複合的機率增加，而有較佳的發光效率；有摻雜氯的硒化鎘量子點半高寬也有增加的情形，這可能是由於摻雜氯令硒化鎘量子點尺寸分布不均所造成的效果；由變溫的光激螢光光譜我們也發現摻雜氯的硒化鎘量子點其活化能較未摻雜的樣品來的高，這表示摻雜而導致過多的電子即使有部分被非輻射中心捕捉，仍有較高的機率與電洞複合；最後我們將樣品進行加熱兩小時的實驗，結果發現有摻雜氯的硒化鎘量子點因熱而導致發光效率的衰減的情形有大幅度改善；以上結果都顯示摻雜氯的硒化鎘量子點非常適合運用在發光二極體元件中。
並列摘要
Abstract We investigate the characteristics of Cl-doped CdSe quantum dots grown by molecular beam epitaxy on GaAs substrates. The room temperature PL shows the Cl-doped CdSe quantum dots have better light emission efficiency. The temperature dependent PL shows the activation energy of Cl-doped CdSe quantum dots is more than undoped CdSe quantum dots, that was due to that the doped quantum dots have much more electrons, even though some captured by non-radiative center but there still have enough carriers to recombined with holes. We compare the room temperature PL spectra after annealing the Cl-doped CdSe quantum dots and undoped quantum dots by 150 ℃ 2 hours. We found the doped CdSe quantum dots have better thermal-stability. All the result indicated the Cl-doped CdSe quantum dots are suitable for the applications of light emitting diodes.