GaInNas/GaAs QW Based Structures to Compensate Parasitic Effect of Quantum-Confined Stark Effect in Photodetector Applications

The inhomogeneities of multicomponent semiconductor alloys, as well as phase segregation, can be utilized for enhancement of photodetector absorption properties and thus its efficiency. In this paper, the influence of external electric field on the probability of light absorption in the GaInNAs quantum well is discussed. Both phenomenon: indium and nitrogen composition gradient as well as step-like quantum well are applied to design the QW with compensation of the Quantum-Confined Stark Effect (QCSE) Parasitic effect of QCSE results from decrease of the wave functions overlapping in the QWs placed in reverse biased junction, which finally decrease the efficiency of the photodetector

Photonic Devices with Siloxane Membranes

Expansion of polymer nanotechnologies accelerated the polymer photonics. This technology brings novel interesting results with simple and cheap solutions. Promising candidates are siloxane materials as polydimethyl siloxane (PDMS) and polydimethyldiphenyl siloxane (PDMDPS) with unique mechanical and optical properties. In this paper we present laser lithography technologies in a combination with siloxane embossing for fabrication of different grating structures with periodical and quasiperiodical symmetry. We present the concept of siloxane based thin membranes with patterned surface as an effective diffraction element for modification of radiation pattern diagram of light emitting diodes (LEDs) and enhancement of angular detection properties of photodiodes. Also the combination of PDMDPS and PDMS was used for fabrication of a waveguide structure with surface relief Bragg grating. Optical properties of fabricated LEDs are investigated by near- and far-field measurements. Transmission properties of fabricated waveguide are investigated by optical spectrum analyzer

DLTS Study of InGaAsN/GaAs p-i-n Diode

The paper presents an in-depth DLTS characterization of the p-i-n structure based on the InGaAsN/GaAs triple quantum well. Three DLTS evaluation methods were used for evaluation of the measured DLTS spectra. The results of all evaluation methods are compared and discussed. One of the evaluation methods that were used is a novel numerical algorithm that was recently developed. Several material and growth defects were identified. Emission from the quantum well was also observed and identified. The parameters of the energy levels were calculated and compared. The studied InGaAsN/GaAs structure is promising candidate for the solar cell applications and the further refinement of the growth process and technology is encouraged

A novel electrospun ZnO nanofibers biosensor fabrication

In this study, a ZnO nanofiber biosensor design is reported. ZnO nanofibers were obtained by electrospinning process followed by calcination. As a novel fabrication method, amorphous thin film of AIN(x) deposited by reactive magnetron sputtering, was proposed as a protective and stabilizing layer in subsequent technological processes. This allowed to use photolithography techniques for fabrication of the electrospun ZnO nanofibers sensor structures which is first time reported. The wet etching of AIN protective layer, Ti/Au ohmic contacts to ZnO fibers and polyimide passivating film have completed the design. Topography of the sensor structure was investigated using AFM and SEM. I-V measurements made for electrical characterization of ohmic contacts and nanofibers in different solutions environments including biological agent are reported