Applied Physics Letters · 1998 · 50 citations · 10 references
EngineeringMaterials SciencePhysicsElectronic MaterialsOptoelectronicsSemiconductor MaterialsElectronic Band StructureOptical Properties Of SemiconductorsQuantum WellsSemiconductor HeterostructuresSemiconductor PhysicsWide Band Gap SemiconductorsDark CurrentMolecular Beam EpitaxyQuantum Well Band StructureQuantum Well GrowthQuantum Well StructuresStrain EffectsStrained Quantum WellsVoltage
The dark current as a function of temperature and infrared absorption of the p-doped In0.15Ga0.85As/Al0.45Ga0.55As multiple quantum well structures grown by molecular beam epitaxy are investigated. The dark current Id of the structure is found to be basically symmetrical over a voltage range from −10 to +10 V. It is about 10−9 A at a bias of 1 V at 80 K, more than two orders of magnitude lower than that reported for p-doped GaAs/AlGaAs QW structures with the same size. It is also found that Id is proportional to T exp[−(EC–EF)/kT] at 70 K and above while at temperatures below 30 K it does not change significantly. The EC–EF decreases with the increase in bias in an exponential form, due likely to energy bandgap bending. A strong infrared absorption peaked at a wavelength of 10.7 μm is in excellent agreement with the estimated value of 10.4 μm.
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