利用邊緣減薄結構提升量子點紅外光偵測器操作溫度之研究

Abstract

本文的研究目標是提升量子點紅外光偵測器的操作溫度。主要嘗試利用邊緣減薄結構；結合表面原子層沉積氧化鋁層的邊緣減薄結構，減低元件表面漏電流，提高操作溫度。 本文在第一個實驗中，研究了在上電極層、量子點層，兩個不同位置的邊緣減薄結構對元件性能的影響。所採用的邊緣減薄結構厚度約為100~200 nm，寬度約為10 μm。實驗結果發現，邊緣減薄結構並無法有效降低量子點紅外光偵測器的暗電流並提升操作溫度。 本文在第二個實驗中，結合了邊緣減薄結構與表面原子層沉積的氧化鋁層，嘗試提升元件的操作溫度。所沉積的氧化鋁約為10 nm厚。實驗結果發現，結合邊緣減薄結構與表面原子層沉積氧化鋁層仍無法顯著提升量子點紅外光偵測器的操作溫度。但位於量子點層的邊緣減薄結構與表面原子層沉積氧化鋁層結合後，能夠抑制元件的電流，使元件能在更高的電壓下工作。 在本文的實驗中，無法藉由邊緣減薄結構，以及與表面原子層沉積氧化鋁層結合的邊緣減薄結構顯著提升量子點紅外光偵測器的操作溫度。相關研究仍有待進一步的探討。

In this thesis, the edge thinning structure with width of 10 μm and thickness of 100~200 nm and the edge thinning structure combined with surface passivation layer Al2O3 with thickness of 10 nm are adopted on n-i-n InAs/GaAs QDIPs to enhance the operation temperature of n-i-n InAs/GaAs quantum dot infrared photodetectors. In the first experiment, edge thinning structure with different depths on QDIPs is investigated. It is found that edge thinning structure at top contact layer and quantum dot layer both can’t significantly reduce the dark current and enhance the operation temperature of QDIPs in this experiment. In the second experiment, the combination of edge thinning structure and surface passivation layer Al2O3 is investigated. It is found that the combination of edge thinning structure and surface passivation layer Al2O3 can’t significantly reduce the dark current and enhance the operation temperature of QDIPs in this experiment. However, the combination of edge thinning structure at quantum dot layer and surface passivation layer Al2O3 can reduce the current by 2 orders of magnitude so the device can work at higher bias voltage. In summary, the edge thinning structure and that combined with surface passivation layer Al2O3 haven’t enhanced the operation temperature of QDIPs. It may require more advanced investigation.