- 學位論文
量子井崁入層分子束磊晶技術及其光激螢光譜量測
Photoluminescence measurement and molecular beam epitaxy of quantum well structure with inserted layer
摘要
利用分子束磊晶技術將二個原子層的碲x硒1-x化鋅(x小於0.01)薄膜崁入在第一型的硒化鋅/硒化鎘鋅多重量子井結構的井中央，並藉由光激螢光譜量測其在低溫下的光學特性。因為碲硒化鋅崁入層在硒化鋅/硒化鎘鋅多重量子井中央，可提供稀疏且近似獨立的二維碲原子分佈，而碲原子扮演激子的捕捉中心與激子形成碲束縛激子及多碲束縛激子。由於在硒化鋅/硒化鎘鋅多重量子井的量子侷限下，碲束縛激子及多碲束縛激子的光激螢光會隨著硒化鎘鋅量子井井寬遞減而愈趨明顯。碲束縛激子的束縛能也隨著硒化鎘鋅量子井的井寬遞減而呈現增強的現象。另一組樣品則為第二型的硒化鋅/碲硒化鋅多重量子井結構，並在碲硒化鋅層中央崁入厚度為1.0奈米的硒化錳鋅薄膜。由於硒化錳鋅的崁入，而使碲硒化鋅層的電洞受到微擾，因此碲原子團束縛激子的躍遷能量比無崁入層時的躍遷能量還高，並且觀測到碲原子團束縛激子的躍遷能量也會隨著碲硒化鋅的井寬變窄而呈藍位移現象。
並列摘要
A thin ZnSe1-xTex (x < 0.01) layer with only two atomic monolayers was inserted at the center of a Type I ZnSe/ZnCdSe multiple quantum well by molecular beam epitaxy (MBE). Optical property at low temperature was studied by photoluminescence (PL). We find that ZnSeTe inserted layer can supply rare and almost isolated two–dimensional Te atoms at the center of ZnSe/ZnCdSe multiple quantum well (MQW), also Te atoms play the roll of exciton trapping centers to form a single Te bound exciton (X/Te) and many Te bound exciton (X/Ten). Due to quantum confinement photoluminescence intensity of X/Te and X/Ten becomes more pronounced as well width of ZnCdSe layer decreases. The binding energy of X/Te also increases with the decrease of ZnCdSe layer thickness. The other set of sample is a Type II ZnSe/ZnSeTeMQW structure with a 1.0nm ZnMnSe thin layer inserted at the center of ZnSeTe. The insertion of ZnMnSe into ZnSeTe layer results a perturbation to the hole state inside ZnSeTe layer. The transition energy of Te cluster bound exciton in the quantum well without inserted layer is lower than that of inserted QW. A blue shift in transition energy of Te cluster bound exciton is observed as ZnSeTe well width decreases.