| 1. |
- Hoglund, L, et al.
(författare)
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Selective optical doping to predict the performance and reveal the origin of photocurrent peaks in quantum dots-in-a-well infrared photodetectors
- 2009
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Ingår i: INFRARED PHYSICS and TECHNOLOGY. - Exeter : Elsevier BV. - 1350-4495 .- 1879-0275. ; 52:6, s. 272-275
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Tidskriftsartikel (refereegranskat)abstract
- Resonant optical pumping across the band gap was used as artificial doping in InAs/In0.15Ga0.85As/GaAs quantum dots-in-a-well infrared photodetectors. Through efficient filling of the quantum dot energy levels by simultaneous optical pumping into the ground states and the excited states of the quantum dots, the response was increased by a factor of 10. Low temperature photocurrent peaks observed at 120 and 148 meV were identified as intersubband transitions emanating from the quantum dot ground state and the quantum dot excited state, respectively by a selective increase of the electron population in the different quantum dot energy levels.
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| 2. |
- 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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| 3. |
- Höglund, Linda, 1974-, et al.
(författare)
-
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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| 4. |
- Höglund, Linda, 1974-, et al.
(författare)
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Origin of photocurrent in lateral quantum dots-in-a-well infrared photodetectors
- 2006
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Ingår i: Applied Physics Letters. - New York : American Institute of Physics. - 0003-6951 .- 1077-3118. ; 88:21
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Tidskriftsartikel (refereegranskat)abstract
- Interband and intersubband transitions of lateral InAs/In0.15Ga0.85As dots-in-a-well quantum dot infrared photodetectors were studied in order to determine the origin of the photocurrent. The main intersubband transition contributing to the photocurrent (PC) was associated with the quantum dot ground state to the quantum well excited state transition. By a comparison between intersubband PC measurements and the energy level scheme of the structure, as deduced from Fourier transform photoluminescence (FTPL) and FTPL excitation spectroscopies, the main transition contributing to the PC was identified.
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| 5. |
- Park, M. S., et al.
(författare)
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InAs/GaAs p-i-p quantum dots-in-a-well infrared photodetectors operating beyond 200 K
- 2014
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Ingår i: Electronics Letters. - Stevenage, United Kingdom : Institution of Engineering and Technology (IET). - 1350-911X .- 0013-5194. ; 50:23, s. 1731-1732
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Tidskriftsartikel (refereegranskat)abstract
- High-temperature operating performance of p-i-p quantum dots-in-awell infrared photodetectors (QDIPs) is successfully demonstrated. The optically active region consists of 10 layers of p-doped selfassembled InAs quantum dots (QDs) asymmetrically positioned in In0.15Ga0.85As quantum wells (QWs). The dark current is suppressed by an incorporated superlattice (SL) structure composed of 10 pairs of AlGaAs/GaAs heterostructure. The very low recorded dark current makes the fabricated p-i-p QDIPs suitable for high-temperature operation. The measured photoresponse reveals broad mid-wave infrared (MWIR) detection up to 200 K.
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