Light Sources for Semiconductor Manufacturing

 

We have gathered some of the peer-reviewed research conducted using our sources below. 

 

Fundamental Aspects of Photoinduced Charge Flow at a Quantum Dot Sensitized Single Crystal TiO2 Semiconductor Interface

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The fundamental aspects of charge transfer from photoexcited CdSe quantum dots to a single crystal of TiO2, a wide band gap metal oxide semiconductor, were investigated and compared with that of a dye-sensitized system in relation to the operation of quantum-dot-sensitized solar cells (QDSCs) and dye-sensitized solar cells (DSSCs). Due to the stark differences in both physical and electronic properties of quantum dots versus molecular dyes, it was hypothesized that the fundamental behavior of the two systems could differ greatly. The large size and surface area of the quantum dots relative to molecular dyes present the possibility for the positively charged hole to move a greater distance away from the QD/oxide interface during the electron injection process. This increased distance influences the Coulombic interaction between the trapped hole and injected electron, leading to differences and increased complexity of the recombination pathways when compared to the dye system.

 

Characterization of plasmonic hole arrays as transparent electrical contacts for organic photovoltaics using high-brightness Fourier transform methods

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We present a methodology for probing light-matter interactions in prototype photovoltaic devices consisting of an organic semiconductor active layer with a semitransparent metal electrical contact exhibiting surface plasmon-based enhanced optical transmission. We achieve high-spectral irradiance in a spot size of less than 100 μm using a high-brightness laser-driven light source and appropriate coupling optics. Spatially resolved Fourier transform photocurrent spectroscopy in the visible and near-infrared spectral regions allows us to measure external quantum efficiency with high sensitivity in small-area devices (<1 mm2). This allows for rapid fabrication of variable-pitch sub-wavelength hole arrays in metal films for use as transparent electrical contacts, and evaluation of the evanescent and propagating mode coupling to resonances in the active layer.

 

Mueller Matrix Polarimetry: A Powerful Tool for Nanostructure Metrology

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Recently, ellipsometry-based scatterometry has gained more and more attention in semiconductor manufacturing. Among the various types of ellipsometry, Mueller matrix polarimetry (MMP) can obtain up to 16 quantities of a 4×4 Mueller matrix, and consequently, MMP-based scatterometry can acquire much more useful information about the sample. In this paper, the basic principle and instrumentation of MMP are presented, and then the fundamental concept of computational metrology is introduced. Several case studies are finally provided to demonstrate the potential of MMP in nanostructure metrology.