DIAGNOSIS OF SEMICONDUCTOR HETEROSYSTEMS USING THE PHOTOVOLTAIC METHOD

The diagnostic method is as follows: the lateral photo-EMF spectral characteristics are measured, generated in the structure (or device) when illuminated by wavelength light with a near the edge of the basic semiconductor layer. For illustrations of efficiency method the given part of the measurement results for Schottky contact samples with a nitrogen concentration of 5% and a thermal annealing temperature of 900 and 950°C. It has been found that a significant character and a small amplitude of such a characteristic indicates qualitative at a homogeneity and the necessary magnitude of the potential barrier (or barriers), that it is necessary to form to make Schottky contact or other structure. A significant characteristic and a small amplitude of such a characteristic indicates a qualitative one-line and the required value of a potential barrier (or barriers) that must be formed for the manufacture of a semiconductor structure or device. If the spectral characteristic has one maximum and amplitude that is many times higher than the amplitude of a significant characteristic, then this indicates a formed transition layer between components of heterosystems with high, compared with a quasine-power region of semiconductor, conductivity. The presence of such a layer increases the probability breaks down of the microelectronic device. Investigation of the distribution of lateral photours along the metal semiconductor interface compliant interpretation of spectral characteristics features. The linear significant form of distribution of EMF confirms the presence of a transition layer with a lower doping level compared with GaAs. An important feature of the diagnostic method is its non-destructive character, as well as the possibility of applying to semiconductor or devices based on them, in which the photovoltaic effect may occur.

Recent development of UV-B laser diodes

This review paper describes the history of development, current issues, and future expectations of UV-B laser diodes, which are expected to be adopted in various applications such as microfabrication and biotechnology in the near future. In order to achieve room temperature operation of this device, there were several challenges are remained, including the development of a crystal growth technique of high crystalline quality AlGaN that enables a laser oscillation with a low excitation carrier density, and the development of a semiconductor layer structure that simultaneously formation of a desirable optical cavity and injection of high density carriers (operation of high current density) to active layer allowing for laser oscillation. These challenges and the technologies that have overcome them are reviewed. Current status of the device characteristics and future challenges are also discussed.

Computer Simulation of the Semiconductor Nanoelectromechanical Systems AIIBIVAs2 Stability after Attosecond Impulse Exposure

The article deals with computer modeling of responses of multicomponent semiconductor nanoelectromechanical systems of arsenides to an attosecond radiation pulse at cryogenic (T1=77 K) and standard temperatures (T2=298 K). Kinetic curves of relaxation processes in ternary semiconductor nanolayers CdSiAs2, CdGeAs2, ZnSiAs2, ZnGeAs2, and nanolayers of variable composition CdSi1-xGex As2, ZnSi1-xGexAs2, Cd1-xZnxSiAs2 и Cd1-xZnxGeAs2 are obtained. This research reveals the differences in the average relaxation energy of nanolayers that depend on temperature and the amplitudes of energy fluctuations, and the time of reaching the plateau. A comparison with relaxation processes taking place at absolute zero temperatures is demonstrated. The radial distribution functions of atoms in the system before and after relaxation processes caused by impulsive action on the system of atoms in the semiconductor layer are considered. The modification of the peaks corresponding to the coordination spheres of atomic distribution depending on the composition of the nanolayer is described. The regularities of relaxation changes of the first order coordination spheres, as well as the regularities of relaxation destructions of the second and the third order coordination spheres at cryogenic and standard temperatures are revealed.

I-V Curves of an Apigenin Dye and Their Analysis by a New Parabolic Function

A new parabolic function for I-V curves’ analysis has been proposed. The new “analytical tool” provides a simple way to describe photophysical processes at an approximately monolayer surface of a dye-sensitized solar cell. It may now be possible to estimate factors such as hole–electron recombination, surface defects, and electron diffusion at the semiconductor layer. The theoretical approach that was previously reported by our group for predicting the photovoltaic performance of potential dye sensitizers has also been validated. The experimental photovoltaic and DFT/TD-DFT data of apigenin and those of the highly rated black dyes were used for the validation.

Modification of active region of resonant tunnel diode

Interest in the study of mesoscopic structures has grown significantly in recent years. This is primarily due to the development of semiconductor technology, which makes it possible to create structures with sizes of the order of units and tens of nanometers. The linear dimensions of such structures are inferior to the de Broglie wavelength of electrons, so the transport of electrons is determined mainly by their wave properties, which, in turn, leads to a number of new effects. Mesoscopic structures include the resonant tunnel diode (RTD), first proposed by Esaki and Tsu, and which is one of the first nanoelectronic devices. It consists of a semiconductor layer with a fairly narrow band gap, a quantum well (QW) layer located between two semiconductor layers (barriers) with a wider band gap. These layers, in turn, are located between the layers (spacers) of weakly doped narrow semiconductor, followed by highly doped layers of the emitter and collector. There are one or more energy levels of dimensional quantization in the QW. Under the action of bias voltage, the current passes through the RTD only if the emitter contains electrons that can tunnel. Resonant tunneling occurs at the energy level in the QW, and from there to the collector, where the spectrum of energy states is band. RTD has a very high speed of action, for example, it is known that the nonlinear properties of RTD persist up to 104 THz. The RTD is also of great power: it is the only device of nanoelectronics that can be used at room temperatures, and on the VAC of the RTD the areas of negative differential conductivity (NDC) are observed. In this article, the principle of a resonant tunneling diode is revealed, and the phenomena of tunneling in nanophysics are examined in detail. The volt-ampere characteristic (VAC) model of a two-barrier resonance tunnel diode is calculated. The paper investigates how the change of transparency coefficients and the reflection of the potential barrier of a rectangular shape affect the VAC of the RTD. This study can be the basis for further consideration of how the modification of the active region of the resonant tunnel diode affects its characteristics. In addition, the results of the research allow us to estimate qualitatively the energy required by electrons for tunneling through the structure of the RTD.

Enhanced thin-film transistor driven high-aperture in-plane switching liquid crystal displays without common line and black matrix

We developed active-matrix in-plane switching liquid crystal displays (IPS-LCDs) with a new vertical structure composed of thin-film transistors (TFTs) that have an aperture ratio of 60% to reduce energy consumption. The novel TFT has a channel and a back channel made of a hydrogenated amorphous-silicon semiconductor layer sandwiched by thin silicon oxide insulating layers. The transfer characteristics are enhanced by uniformly shifting the threshold voltage to be higher than the maximum LC driving voltage (typically > 5 V). The enhanced TFT characteristics provided with a new driving scheme and shielding electrodes enables both the common line and black matrix to be eliminated. We fabricated an IPS TFT-LCD panel with aperture and contrast ratios that are 160% those of the conventional pixel structure.

Parasitic Current Induced by Gate Overlap in Thin-Film Transistors

As novel applications of oxide semiconductors are realized, various structural devices and integrated circuits are being proposed, and the gate-overlay defect phenomenon is becoming more diverse in its effects. Herein, the electrical properties of the transistor that depend on the geometry between the gate and the semiconductor layer are analyzed, and the specific phenomena associated with the degree of overlap are reproduced. In the semiconductor layer, where the gate electrode is not overlapped, it is experimentally shown that a dual current is generated, and the results of 3D simulations confirm that the magnitude of the current increases as the parasitic current moves away from the gate electrode. The generation and path of the parasitic current are then represented visually through laser-enhanced 2D transport measurements; consequently, the flow of the dual current in the transistor is verified to be induced by the electrical potential imbalance in the semiconductor active layer, where the gate electrodes do not overlap.