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標題: | 砷化銦量子點紅外線偵測器之成長與光電特性 The Growth and Optoelectronic Properties of InAs/AlGaAs/GaAs Quantum Dot Infrared Photodetectors |
作者: | Shen-De Chen 陳顯德 |
指導教授: | 李嗣涔(Si-Chen Lee) |
關鍵字: | 量子點,紅外線偵測器,砷化銦, quantum dot,infrared photodetector,InAs, |
出版年 : | 2005 |
學位: | 博士 |
摘要: | 經由原子力顯微境、掃描式與穿透式電子顯微境、光激放光頻譜的量測,砷化銦量子點的成長機制被深入的研究探討,也觀察到覆蓋在砷化銦量子點上的砷化銦鎵的相分離成長,砷化鎵成長在潤濕層上,砷化銦則被迫落在原有的量子點上,因而增加了量子點的高度,而使發光波長變長。包含了應力考量的等效量子井模型也被建立,用來計算量子點的內部能階,由其中得知絕大部分的應力來自上層的砷化鎵。以砷化鋁鎵或砷化鋁銦鎵作為阻擋層的量子點紅外線偵測器也已成功地研製並分析研究,此外,在砷化銦量子點上覆蓋一層二奈米的砷化鋁鎵更可以成功地研發出具有高效能、窄頻寬的多彩紅外線偵測器,並且找出其響應的物理機制。在這個紅外線偵測器的頻譜響應中,也觀察到負微分電導、響應隨溫度的變化以及可利用快速熱退火來調變的橫向電場模式響應的增強,它們分別以電子的谷間散射、遷移率隨溫度的變化和應變所導致的類似P軌域之第一激發態的能階分裂來解釋,快速熱退火則導致化學鍵的斷裂,因而改變應力。 The growth mechanisms of the InAs QDs were investigated by using AFM, SEM, TEM and PL. Phase separation growth of InGaAs cap layer on InAs QDs was also observed. GaAs tends to fill up the valley between InAs QDs whereas InAs is forced to remain on the dots, which leads to longer emission wavelength. The effective quantum well model including strain was developed to calculate the energy levels inside the InAs QD and successfully interpreted the PL spectra. The stress mainly comes from the upper GaAs cap layer rather than the lower GaAs matrix. A QDIP with AlGaAs or InAlGaAs blocking layers was fabricated and analyzed. By introducing a 2 nm Al0.3Ga0.7As cap layer on 3 (2.2) ML InAs QDs, the high-performance narrow-bandwidth multicolor InAs/AlGaAs/GaAs QDIPs were successfully fabricated. The origins of the responses were explained. The negative differential conductance, temperature-dependent and TE-mode-enhanced responses were observed. The negative differential conductance is due to intervalley scatterings. The temperature-dependent response originates from the electronic mobility as a function of temperature. The enhanced TE-mode responses could be engineered by RTA and explained by the transition from the S-like ground state to the strain-induced splitting of P-like first excited states, and the RTA process changes the stress inside InAs QDs due to the bond breaking. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/35037 |
全文授權: | 有償授權 |
顯示於系所單位: | 電機工程學系 |
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