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- Höglund, Linda, 1974-, et al.
(författare)
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Bias and temperature dependence of the escape processes in quantum dots-in-a-well infrared photodetectors
- 2008
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Ingår i: Applied Physics Letters. - New York : American Institute of Physics (AIP). - 0003-6951 .- 1077-3118. ; 93:10, s. 103501-
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Tidskriftsartikel (refereegranskat)abstract
- The performance of quantum dots-in-a-well infrared photodetectors (DWELL IPs) has been studied by means of interband and intersubband photocurrent measurements as well as dark current measurements. Using interband photocurrent measurements, substantial escape of electrons from lower lying states in the DWELL structure at large biases was revealed. Furthermore, a significant variation in the escape probability from energy states in the DWELL structure with applied bias was observed. These facts can explain the strong temperature and bias dependence of both photocurrent and dark currents in DWELL IPs.
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| 2. |
- Höglund, Linda, 1974-, et al.
(författare)
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Bias mediated tuning of the detection wavelength in asymmetrical quantum dots-in-a-well infrared photodetectors
- 2008
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Ingår i: Applied Physics Letters. - New York : AIP Publishing. - 0003-6951 .- 1077-3118. ; 93:20
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Tidskriftsartikel (refereegranskat)abstract
- Bias-mediated tuning of the detection wavelength within the infrared wavelength region is demonstrated for quantum dots-in-a-well and dots-on-a-well infrared photodetectors. By positioning the InAs quantum dot layer asymmetrically in an 8 nm wide In0.15Ga0.85As/GaAs quantum well, a shift in the peak detection wavelength from 8.4 to 10.3 mu m was observed when reversing the polarity of the applied bias. For a dots-on-a-well structure, the peak detection wavelength was tuned from 5.4 to 8 mu m with small changes in the applied bias. These tuning properties could be essential for applications such as modulators and dual-color infrared detection.
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| 3. |
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| 4. |
- Höglund, Linda, et al.
(författare)
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Tuning of the detection wavelength in quantum dots-in-a-well infrared photodetectors
- 2008
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Ingår i: Proceedings of SPIE, 6940, Infrared Technology and Applications XXXIV, 694002. - : SPIE. - 9780819471314
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Konferensbidrag (refereegranskat)abstract
- In this study, bias mediated tuning of the detection wavelength within the infrared wavelength region is demonstrated for quantum dots-in-a-well (DWELL) infrared photodetectors. In DWELL structures, intersubband transitions in the conduction band occur from a discrete state in the quantum dot to a subband inthe quantum well. Compared to "conventional" quantum dot infrared photodetectors, where the transitions take place between different discrete bands in thequantum dots, new possibilities to tune the detection wavelength window are opened up, partly by varying the quantum dot energy levels and partly by adjusting the width and composition of the quantum well. In the DWELL structure used, an asymmetric positioning of the InAs quantum dot layer in a 8 nm wide In0.15Ga0.85As/GaAs QW has been applied which enables tuning of the peak detection wavelength within the long wavelength infrared (LWIR; 8 - 14 gm) region. When the applied bias was reversed, a wavelength shift from 8.5 to 9.5 mu m was observed for the peak position in the spectral response. For another DWELL structure, with a well width of 2 nm, the tuning range of the detector could be shifted from the medium wavelength infrared (MWIR; 3-5 mu m) region to the LWIR region. With small changes in the applied bias, the peak detection wavelength could be shifted from 5.1 to 8 mu m. These tuning properties ofDWELL structures could be essential for applications such as modulators and two-colour infrared detection. © (2008) COPYRIGHT SPIE--The International Society for Optical Engineering.
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