Home  About us  Contact
 

Quantum Dot Layers (quantum + dot_layer)

Distribution by Scientific Domains
Physics and Astronomy100%

Selected Abstracts

Nanowire,quantum-dot,polymer solar cell

PHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 9 2008
A. Nadarajah
Abstract We report first results on a new solar cell structure which incorporates n-type ZnO nanowires, an undoped CdSe layer, obtained from quantum dot precursors, and a p-type polymer layer as the main components. In the fabrication process the quantum dot layer is converted to a conformal ,30 nm thick polycrystalline film. The fabrication of the cell occurs in lab air at temperatures below 100 °C. Several intermittent annealing steps raise the energy conversion efficiency to approximately 1%. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Optical properties and modal gain of InGaN quantum dot stacks

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue S2 2009
Joachim Kalden
Abstract We present investigations of the optical properties of stacked InGaN quantum dot layers and demonstrate their advantage over single quantum dot layer structures. Measurements were performed on structures containing a single layer with quantum dots or threefold stacked quantum dot layers, respectively. A superlinear increase of the quantum dot related photoluminescence is detected with increasing number of quantum dot layers while other relevant GaN related spectral features are much less intensive when compared to the photoluminescence of a single quantum dot layer. The quantum dot character of the active material is verified by microphotoluminescence experiments at different temperatures. For the possible integration within optical devices in the future the threshold power density was investigated as well as the modal gain by using the variable stripe length method. As the threshold is 670 kW/cm2 at 13 K, the modal gain maximum is at 50 cm,1. In contrast to these limited total values, the modal gain per quantum dot is as high as 10,9cm,1, being comparable to the IIVI and III-As compounds. These results are a promising first step towards bright low threshold InGaN quantum dot based light emitting devices in the near future (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Characterization of highly stacked InAs quantum dot layers on InP substrate for a planar saturable absorber at 1.5 µm band

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 3 2006
Jun Inoue
Abstract We examined the absorption saturation properties in the 1.5 µm band of novel highly stacked InAs quantum dot layers. The transmission change at vertical incidence based on the saturable absorption of the quantum dots was more than 1%. This value is as large as the reflection changes of previously reported 1-µm-band quantum dot saturable absorber with interference enhancement. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Persistent photoconductivity in quantum dot layers in InAs/GaAs structures

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 4 2003
V. A. Kulbachinskii
Abstract We synthesized InAs/GaAs structures with quantum dot layers and investigated electron (Si doping) lateral transport in the temperature interval 0.05 K < T < 300 K in the dark and under illumination by light over a wide interval of wavelengths in magnetic fields up to 6 T. All the samples exhibited a positive persistent photoconductivity at T < 250 K. Without illumination in the high carrier density samples the Shubnikov,de Haas effect and the quantum Hall effect were observed. Low carrier density samples showed a 2D Mott variable range hopping conductivity. The morphology of the quantum dot layers was investigated by atomic force microscopy (AFM). The length of localization exceeds the average quantum dot size and correlates very well with the quantum dot cluster size obtained by AFM. [source]