Applied Physics Letters · 2008 · 55 citations · 20 references
EngineeringElectrical EngineeringMaterials ScienceOptoelectronicsSemiconductor DevicesSemiconductor MaterialsOptoelectronic DevicesOptoelectronic MaterialsPhotodetectorsQuantum ConfinementQuantum DotsSemiconductor PhysicsDetector Quantum EfficiencyElectronic Density Of StatesExcited Electronic StatesQuantum Dot DevicesQuantum Dot PhotodetectorsQuantum EfficiencyQuantum Well Infrared PhotodetectorsSemiconductor Quantum Dots
We demonstrate the high quantum efficiency InAs∕In0.15Ga0.85As dots-in-a-well (DWELL) quantum dot infrared photodetectors (QDIPs). A thin Al0.3Ga0.7As layer was inserted on top of the InAs quantum dots (QDs) to enhance the confinement of QD states in the DWELL structure. The better confinement of the electronic states increases the oscillation strength of the infrared absorption. The higher excited state energy also improves the escape probability of the photoelectrons. Compared with the conventional DWELL QDIPs, the quantum efficiency increases more than 20 times and the detectivity is about an order of magnitude higher at 77K.
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Subhananda Chakrabarti, Adrienne D. Stiff‐Roberts, P. Bhattacharya et al. · IEEE Photonics Technology Letters · 2004 · 165 citations