Controlling the Response of Plasmonic Nano-Antennas through Gap-Loading

Unlike previously reported works, in this paper, we aim to create a link between the radiating elements and the proposed device at a distance, so that the emission can be distantly and freely manipulated. We present here a new type of device, using nonlinear hybrid antenna-semiconductor interaction. We observe a picosecond transient response from the antenna that cannot be explained by either pure or antenna nonlinearities independently. We have shown that optical pumping of antenna-semiconductor interaction leads to a local reduction of the free-carrier density in the substrate. The transient nonlinear response of the antenna-semiconductor interaction hybrid shows a redshift of the plasmon resonance, as opposed to transient bleaching on SiO2.

Исследование омических контактов мощных фотоэлектрических преобразователей

Ohmic contacts of power AlGaAs/GaAs-based photovoltaic converters were studied, and a technique for their fabrication was developed. Effect of the doping level of the contact layer on the free-carrier density and the contact resistivity was examined. A technique for fabrication of 2- to 4-μm-thick ohmic contacts with electrochemical deposition of gold layers was studied. The effect of deposition modes on the surface morphology of ohmic contacts and their solidity and conductivity was revealed.

Enhanced Scanning Nonlinear Dielectric Microscopy with Stepwise dC/dV and dC/dz Imaging—Achieving Qualitative, Quantitative and Artifact-Free Carrier Density Profiling of Semiconductor Devices

High-resolution and high-sensitivity detection of free carriers in semiconductors is critical due to the trend of device miniaturization and diversification. To address this need, the AFM-based techniques of scanning spreading resistance microscopy, scanning capacitance microscopy, scanning nonlinear dielectric microscopy (SNDM), scanning microwave impedance microscopy, and scanning microwave microscopy are used. This paper demonstrates enhanced SNDM with stepwise dC/dV and dC/dz imaging, qualitative analysis, quantitative analysis, and artifact-free carrier-density profiling of semiconductor devices. The trace mode in enhanced SNDM is switched between contact (dC/dV measurement) state and non-contact (dC/dz measurement) state for every line scan whereby the sampling intelligent scan mode is switched these states every pixel. Using IMEC Si standards and Si power MOSFET as examples demonstrates that this SNDM methodology can provide qualitative, quantitative, and artifact-free carrier density profiling of semiconductor devices.

Особенности электрохимического вольт-фарадного профилирования арсенид-галлиевых светоизлучающих и pHEMT-структур с квантово-размерными областями

GaAs light-emitting (LED) and HEMT structures with δ-doped regions, InGaAs/GaAs quantum wells, and surface layers of InAs/GaAs quantum dots were studied by means of the electrochemical capacitance- voltage profiling technique. The concentration depth profiles of free charge carriers were obtained. Charges accumulated in quantum wells and quantum dots, as well as the doping levels of the emitter and δ layers were determined. The band structure and free carrier density distribution over the depth of the samples with different quantum well geometry were simulated. The specific features of electrochemical capacitance- voltage profiling in different heterostructure types are analyzed. A method of integration of capacitance- voltage curves at each etching stage was suggested. This method provides the efficient separation of responses from closely located layers, particularly the quantum well and δ layer.

Eye-readable gasochromic and optical hydrogen gas sensor based on CuS–Pd

A CuS–Pd nanohybrid functions as a naked eye detectable H2 chemochromic and optical sensor by taking an advantage of a decrease in localized surface plasmon resonance due to a reduction in free carrier density.