量子點紅外線偵測器之研究

Abstract

利用自組織法來成長砷化銦 / 砷化鎵的量子點紅外線偵測器，並藉由調整量子點密度、摻雜濃度及在量子點之間所成長的高能隙之砷化鋁鎵，我們再度將偵測器的暗電流降低了幾個數量級。其吸收光譜的波長峰值約在6.5 ，同時，我們也觀察到正向入射的吸收。最佳的偵測度在偏壓為0.8V時有 1.9 x 1010 cmHz1/2 / W，此時溫度為77K。如理論所預測的，我們也觀察到高響應度和高增益。結果顯示，我們所提出的新結構能改進原來砷化銦 / 砷化鎵結構的量子點紅外線偵測器。

We have designed and fabricated self-assembled InAs-GaAs quantum dot infrared photodetectors which adjusts the dot’s density and impurity’s doping level and growths AlGaAs between quantum dots to decrease dark current. Compare to traditional InAs/GaAs QDIP, our new structure successfully decrease dark current by several order. The intersubband transition peak is observed at the wavelength of 6.5 and shows encouraging normal incident performance characteristic, with detectivity of at a bias of 0.8V and T = 77K . It also shows large responsivity and photoconductive gain which just corresponds to theoretical prediction . The measurements show that our new structure indeed improves original QDIP .