Дисперсия плазменных колебаний в аморфных халькогенидных полупроводниках

Thin films of amorphous chalcogenide semiconductors on a silicon crystal are studied by the method of plasma vibration dispersion and the asymmetry of the number of electrons in the zone of formation of the total external reflection of X-rays and the excitation of plasmons is calculated. Loop-like dispersion curves were observed and the average plasmon energies and the associated internal mechanical stresses and polarization of the studied films were determined. The absence of internal mechanical stresses and polarization in an amorphous semiconductor film of molybdenum sulfide is found.

Fabrication of Microbolometer Arrays Based on Polymorphous Silicon–Germanium

This work reports the development of arrays of infrared sensors (microbolometers) using a hydrogenated polymorphous silicon–germanium alloy (pm-SixGe1-x:H). Basically, polymorphous semiconductors consist of an amorphous semiconductor matrix with embedded nanocrystals of about 2–3 nm. The pm-SixGe1-x:H alloy studied has a high temperature coefficient of resistance (TCR) of 4.08%/K and conductivity of 1.5 × 10−5 S∙cm−1. Deposition of thermosensing film was made by plasma-enhanced chemical vapor deposition (PECVD) at 200 °C, while the area of the devices is 50 × 50 μm2 with a fill factor of 81%. Finally, an array of 19 × 20 microbolometers was packaged for electrical characterization. Voltage responsivity values were obtained in the range of 4 × 104 V/W and detectivity around 2 × 107 cm∙Hz1/2/W with a polarization current of 70 μA at a chopper frequency of 30 Hz. A minimum value of 2 × 10−10 W/Hz1/2 noise equivalent power was obtained at room temperature. In addition, it was found that all the tested devices responded to incident infrared radiation, proving that the structure and mechanical stability are excellent.

Systematic Investigation of the Electrochemical Properties of Natural Melanin for Various Electrode Cells

Melanin is an organic semiconductor from a broad class of functional macromolecules found in nature. It has hybrid properties of an amorphous semiconductor. However, natural melanin has not been widely studied; this is partially due to the lack of processing methods, as melanin is generally extracted and measured as a powder. Thus, better electrical methods are required; one possible solution is the use of electrochemical synthesis. We investigated the electrochemical properties of melanin at different degrees of acidity and for various electrode cells. The electrochemical properties of natural melanin were studied using two different techniques: the constant potential method and cyclic voltammetry. This could allow different types of charge transport and make melanin a contender in this rapidly growing field. Natural melanin is believed to be a hybrid conductor where the dominant charge carriers change between electrons and protons as the acidity degree and water concentration change. Biocompatible and biodegradable features make melanin useful for electrochemical energy storage and it could be an attractive candidate for applications in bioelectronics and electronics devices.

Modulating Band Gap of Boron Doping in Amorphous Carbon Nano-Film

Amorphous carbon (a-C) films are attracting considerable attention to due their large optical band gap (Eopt) range of 1–4 eV. But the hopping conducting mechanism of boron doping a-C (a-C:B) is still mysterious. To exploring the intrinsic reasons behind the semiconductor properties of a-C:B, in this work, the boron doping a-C (a-C:B) nano-film was prepared, and the growth rate and Eopt changing were analyzed by controlling the different experimental conditions of magnetron sputtering. A rapid deposition rate of 10.55 nm/min was obtained. The Eopt is reduced from 3.19 eV to 2.78 eV by improving the substrate temperature and sputtering power. The proportion of sp2/sp3 increasing was uncovered with narrowing the Eopt. The shrinking Eopt can be attributed to the fact that boron atoms act as a fluxing agent to promote carbon atoms to form sp2 hybridization at low energy. Furthermore, boron atoms can impede the formation of σ bonds in carbon atom sp3 hybridization by forming B–C bonds with high energy, and induce the sp3 hybridization transfer to sp2 hybridization. This work is significant to further study of amorphous semiconductor films.