砷化銦鎵量子環之成長與光電特性及其在偵測器上之應用

The Growth and Optoelectronic Properties of In(Ga)As Quantum Ring and its Application in Infrared Photodetectors

戴忠弘(Jong-Horng Dai)

指導教授 ： 李嗣涔

國立臺灣大學/電機資訊學院/電子工程學研究所/博士(2007年)

https://doi.org/10.6342/NTU.2007.01051

摘要

經由原子力顯微鏡、穿透式電子顯微鏡、與光激放光頻譜的量測，砷化銦鎵量子環及其前身砷化銦量子點的成長機制與成長條件的關係被深入的探討。研究長晶後冷却基板的方式對表面量子點形貎之影響發現立刻關加熱器可以避免降溫對表面量子點形貌產生嚴重的影響。量子點在退火過程中，銦吸附原子在試片上移動造成的尺寸重新分佈及熟化效應，及觀察到量子點的彈性形變。當砷化銦之覆蓋小於臨界厚度時,經由退火可以看到由應力導致試片表面銦吸附原子聚集形成三度空間量子點。在本論文中將不同的量子點大小的結構放在量子點紅外線偵測器中，研究其特性發現可在中紅外波段5至10微米中調整偵測響應波長，其特性與量子點尺寸影響能隙大小有關。在量子環方面，利用不同厚度之薄層砷化鎵來覆蓋砷化銦量子點，觀察到覆蓋在砷化銦上砷化鎵薄層對量子點的解潤濕現象，應力導致量子點中心擴出成量子環的形成過程，及其光電特性與前身砷化銦量子點高寬比的對應關係。運用砷化鎵薄層厚度調整量子環發光波長位移與表面形貌影像的變化，建立出量子環形成模型。最後，應用砷化銦鎵量子環結構取代量子點紅外線偵測器中，成功地研發出廣波域，截止頻率長達兆赫波的量子環紅外線偵測器。

關鍵字

砷化銦鎵 ； 量子環 ； 兆赫波 ； 紅外線偵測器

並列摘要

The growth mechanisms of the In(Ga)As quantum rings (QRs) and its precursors InAs quantum dots (QDs) were investigated by using atomic force microscopy (AFM), transmission electron microscope (TEM) and photoluminescence (PL). The substrate cooling methods on the morphology of surface QDs were studied, it was discovered that turning off power immediately after growth could avoid variation in surface morphology of QDs significantly. Ripening and In adatoms migration results in size redistribution during the QD annealing time, and the elastic relaxation of QDs was also observed. Strain induced In adatoms aggregation to 3D InAs island by annealing was found when the InAs coverage is below critical thickness. The QDIPs with various size QDs were fabricated and analyzed. The detection peak of QDIPs was tailorable from 5 to 10 um. It is because the QD size influences the absorption band of QDIPs. During the growth of QR, dewetting phenomenon occurs when the GaAs capped on InAs QDs are annealed, the thickness of thin GaAs capped layer was sequentially increased to study the strain effect on the transformation of small to large InAs islands to ring structure, and the relationship between the optical properties and morphology was observed. The aspect ratio of InAs QD will affect the shape of In(Ga)As QR. Finally the In(Ga)As/GaAs quantum ring infrared photodetector are analyzed in detail. By employed a thin GaAs layer to tailor the cutoff wavelength of QRIP to 100 um, the terahertz QRIP was fabricated successfully. The mechanism responsible for the far infrared response was explained.

並列關鍵字

In(Ga)As ； Quantum Ring ； Terahertz ； Infrared Photodetector

參考文獻

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