Quantum well

About: Quantum well is a research topic. Over the lifetime, 44627 publications have been published within this topic receiving 674023 citations. The topic is also known as: QW & quantum potential well.

Direct demonstration of a misfit strain‐generated electric field in a [111] growth axis zinc‐blende heterostructure

Abstract: We report the first direct demonstration of a strain‐generated built‐in electric field in a (111) oriented strained‐layer heterostructure. We present a model which describes the accommodation of the misfit strain in a lattice‐mismatched quantum well, and the resulting generation of a longitudinal electric field via the piezoelectric effect. On a (111)B GaAs substrate, we grew the quantum well in the intrinsic region of a p‐i‐n diode such that the strain‐generated electric field in the quantum well opposes the weaker built‐in electric field of the diode. Under reverse bias operation, photoconductivity measurements show a quadratic blue shift of the quantum well electroabsorption peaks, in contrast to the red shifts normally observed in the quantum‐confined Stark effect. The measured blue shifts demonstrate an electric field strength of 1.7×105 V/cm, which agrees with theory to within the accuracy of the measured sample characteristics.

Temperature dependence of photoluminescence from GaAs single and multiple quantum‐well heterostructures grown by molecular‐beam epitaxy

Abstract: The photoluminescence (PL) from GaAs/AlxGa1−xAs single and multiple quantum well (QW) heterostructures grown by molecular‐beam epitaxy (MBE) has been studied in the temperature range 10

InGaN/GaN Core–Shell Single Nanowire Light Emitting Diodes with Graphene-Based P-Contact

Abstract: We report on the demonstration of MOVPE-grown single nanowire InGaN/GaN core–shell light emitting diodes (LEDs) with a transparent graphene contact for hole injection. The electrical homogeneity of the graphene-contacted LED has been assessed by electron beam induced current microscopy. By comparing graphene-contacted and metal-contacted nanowire LEDs, we show that the contact layout determines the electroluminescence spectrum. The electroluminescence changes color from green to blue with increasing injection current. High-resolution cathodoluminescence on cleaved nanowires allows the location with high precision of the origin of different emitted wavelengths and demonstrates that the blue peak originates from the emission of the radial quantum well on the m-planes, whereas the green peak arises from the In-rich region at the junction between the m-planes and the semipolar planes. The spectral behavior of the electroluminescence is understood by modeling the current distribution within the nanowire.

Optical devices featuring textured semiconductor layers

Abstract: A semiconductor sensor, solar cell or emitter or a precursor therefore having a substrate and textured semiconductor layer deposited onto the substrate. The layer can be textured as grown on the substrate or textured by replicating a textured substrate surface. The substrate or first layer is then a template for growing and texturing other semiconductor layers from the device. The textured layers are replicated to the surface from the substrate to enhance light extraction or light absorption. Multiple quantum wells, comprising several barrier and quantum well layers, are deposited as alternating textured layers. The texturing in the region of the quantum well layers greatly enhances internal quantum efficiency if the semiconductor is polar and the quantum wells are grown along the polar direction. This is the case in nitride semiconductors grown along the polar [0001] or [000-1] directions.