Volume 52, Nº 5 (2016)

The possibility of improving the performance of semiconductor integrated circuits by replacing the silicon layer in metal–insulator–semiconductor (MIS) transistors by a material with higher charge-carrier mobility. It is shown that germanium is best suited for this purpose based on its properties. Developments made in this area in different laboratories both in Russia and abroad are discussed.

Nanowire field-effect transistors are highly sensitive sensor elements used for qualitative and quantitative analyses of biological and chemical substances. Optimization of the operation of the sensor is one of the key ways of increasing their sensitivity. An algorithm for choosing the operation mode of sensors based on silicon-on-insulator transistors is proposed which provides their maximum response during conductivity monitoring in the detection of target particles.

Negative differential resistance in InGaN/GaN ultraviolet laser diodes is demonstrated. Switching between the lower and upper branches of the S-shaped current-voltage characteristic leads to a change in the optical emission power by six orders of magnitude as the current increases from 3 to 15 mA. The occurrence of a negative differential resistance is explained by superlinear injection of charge carriers of the same sign into the high-resistance InGaN quantum well.

The design and characteristics of a three-spectrum multielement photodetector device with a sensitivity range from 0.6 to 12.0 μm, which consists of three arrays of photodetectors having sensitivity ranges 0.6–0.9, 3–5, and 8–12 μm, are described. Methods of fabrication of photodetector arrays, the photodetector device as a whole, and its photoelectric characteristics are presented.

This paper presents a review of studies of the photoelectric properties of PbSnTe:In films obtained by molecular beam epitaxy and photosensitive structures in the far infrared and submillimeter ranges based on these films. The parameters of photodetector arrays of this type and detectors based on doped semiconductors and superconductors are compared. One-dimensional (2×128 elements) and two-dimensional (128 × 128 elements) PbSnTe:In based arrays with a sensitivity threshold of ~22 μm and an operating temperature of T ≤ 16 K are implemented. Under background-free conditions, the noise equivalent power (NEP) was NEP ≤ ¹⁰⁻¹⁸ W/Hz^0.5 at T = 7 K for a black body radiation source at T_BB = 77 K. In the submillimeter range of the spectrum, sensitivity to laser radiation with a wavelength λ ≤ 205 μm and a value NEP ≤ 10⁻¹² W/Hz^0.5 was observed without optimization of the design of the photosensitive element and minimization of the measurement circuit noise. The directions of the development of PbSnTe:In based radiation detectors are considered..

Experiments and simulations are performed to study the formation of silicon nanocrystals (Si-NCs) in multilayer structures with alternating ultrathin layers of SiO₂ and amorphous hydrogenized silicon (α-Si:H) during high-temperature annealing. The effect of annealing on the transformation of the structure of the α-Si:H layers is studied by methods of high-resolution transmission electron microscopy, Raman spectroscopy, and photoluminescence spectroscopy. The conditions and kinetics of Si-NC formation are analyzed by the Monte Carlo technique. The type of the resultant crystalline silicon clusters is found to depend on the thickness and porosity of the original amorphous silicon layer located between SiO₂ layers. It is shown that an increase in the thickness of the α-Si layer in the case of low porosity leads to the formation of a percolation silicon cluster instead of individual Si nanocrystals.

The formation of an adsorption layer on the Si(111) surface during sublimation at temperatures of 1000–1100 °C and subsequent quenching at T = 750 °C is studied by methods of insitu ultrahigh-vacuum reflection electron microscopy and exsitu atomic force microscopy. The adatom concentration distribution on an extrawide (~60 μm) atomically flat terrace is determined for the first time, and the diffusion length x_s = 31±2 μm at T = 1000 °C is obtained. The analysis of the temperature dependence of the equilibrium concentration of adatoms near a monatomic step allows pioneering measurements of the energy necessary for adatom detachment from the step and attachment to the terrace E_ad ≈ 0.68 eV. Based on these results, the energy parameters for some atomic processes on the Si(111) surface are estimated.

A method is presented to be used in a computational experiment aimed at studying the internal structure of nano- and mesoscopic objects, i.e., conducting subsystems and quantum phenomena in solid submicron objects, which demonstrate an individual behavior of low-temperature resistance.