Journal of Interface, Thin Film and Low Dimension Systems
Volume:6 Issue: 1, Summer-Autumn 2022

In this study, a numerical model was used to analyze the Auger recombination rate in c-plane InGaN/GaN multiple-‎quantum-well lasers(MQWLD) under hydrostatic pressure. Finite difference techniques were employed to acquire ‎energy eigenvalues and their corresponding eigenfunctions of ‎ MQWLD, and the hole eigenstates ‎were calculated via a 6‎×6 k.p method under applied hydrostatic pressure. It was found that a change in pressure ‎up to 10 GPa increases the carrier density up to‎ ‎0.75×1019 cm-3 and ‎0.56×1019cm-3 ‎ for the holes and electrons, ‎respectively, and the effective band gap. Based on the result, it could decrease the exaction binding energy, rise the ‎electric field rate up to 0.77 MV/cm ‎, and decrease the Auger recombination rate up to 0.6‎×1027cm3s-1 in the ‎multiple-quantum well regions. Also, calculations demonstrated that the hole-hole-electron (CHHS) and electron-electron-hole (CCCH) Auger recombination rate had the largest contribution to the Auger recombination rate. Our ‎studies provided more detailed insight into the origin of the Auger recombination rate drop under hydrostatic ‎pressure in InGaN-based LEDs.‎

In this study, the thermoelectric properties of (6, 0) two sided-closed single-walled boron nitride nanotube ((6, 0) TSC-SWBNNT) in the state without impurity and a single carbon atom impurity instead of boron and nitrogen atoms in the center, left and right The nanotube was investigated in the energy range of -5.5 to 5.5 eV and temperatures of 200, 300, 500, 700, 900, 1100 and 1300 K. The results show that, with the increase in temperature and the creation of impurity, the band gap is affected and becomes noticeably smaller. The highest decrease in band gap is at 1300 K. With increasing temperature, the number of peaks has decreased, which shows that the mobility of electrons and holes has increased and their localization has decreased. As the temperature increases, the height of the thermal conduction peaks increases. But in general, the thermal conduction values are in the range of 9-10 nanoscale. Merit coefficient (ZT) values have increased with the increase in temperature, and the highest values are related to the temperature of 1300 K. The high values of 1 for ZT especially at high temperatures indicates that (6, 0) TSC-SWBNNT are suitable for choosing as thermoelectric material.

This paper, in the first step, introduces a low-power oscillator in the GHz range using the CNFET technology with a Schmitt Trigger, in which the Upper Trigger Point and Lower Trigger Point can be adjusted only through a change in the diameter of the nanotubes of two CNFETs. In this oscillator, the frequency and duty cycle of the output signal can be adjusted via a change in the physical parameters of the transistors and capacitor capacity. The relation of frequency based on Physical parameters is analysed and obtained. The power consumption of the proposed oscillator at 2 GHz frequency is only 2.7 µWatt. The circuit has an output frequency variation range of 50 KHz to 3.5 GHz with a power consumption rate of 0.15 to 12 µwatts in the without offset mode. Through the use of frequency shift in the with offset mode, we can access a wide range of frequency ranges by changing the input voltage. Proposed Circuits are evaluated with the Stanford CNFET Model at 32nm technology in terms of output frequency linear range, power consumption and frequency stability against temperature and process variation and are approved.

Structural stability, electronic and magnetic properties of armchair (5, 5) InP nanotube doped with V, Mn, and Ni are investigated using first-principles calculations. The calculations are performed by the PWscf code. The V, Mn, and Ni metals are replaced by the P position in the InP nanotube. The optimized angles between them and bond lengths are calculated. The results illustrate that the magnetic moment changes are in agreement with the predicted value of Hund’s rule. The results show that Mn-doped InPNT is a ferromagnetic metal, whereas Ni-doped InPNT is a non-magnetic metal. More; importantly doping V in InPNT leads to half-metallic ferromagnetism. Thus, the present results predict that the InP nanotube doped with V is useful for industrial applications, especially in spintronic devices and Nano magnets. To identify the most stable configuration, the formation binding energy and cohesive energy are calculated for all compounds. In the end, the InP nanotube doped with Ni is more stable than others.

TiN thin films are prepared by the DC magnetron sputtering method, and the effect of post annealing treatment on the physical, structural, morphological, and optical properties of TiN layers are investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), and UV-VIS spectrophotometer. Variation of electrical resistivity and film’s hardness are also investigated. Based on the XRD results, increasing annealing temperature would not change film’s stoichiometry, but deteriorates improvement of the films crystalline quality. The as-deposited film with amorphous structure changes to a single-phase crystalline structure that has a preferred orientation along (111) and the polycrystalline structure at higher annealing temperatures. According to SEM images, a dense structure transforms to a denuded zone structure during annealing temperature. The reflectance of TiN films shows a minimum in the visible region indicating a significant increase in the infrared region. The optical band gap energy value increases by increasing the annealing temperature while, the electrical resistivity and hardness values decrease.

In this study, the effect of oxidation temperature and substrate type on the morphology and optical properties of the ZnO films were investigated. The films were prepared by oxidation of metallic zinc layer under air atmosphere. To examine the effect of oxidation on the growth process, the temperatures of 400, 600, and 800 C were considered. To study the impact of the substrate, amorphous quartz and crystalline silicon substrates were used. At 400 C and quartz substrate, the thin layer grows in the form of particles, while it grows in the nanoflake-like shape when using silicon substrate. The surface roughness increases by the increasing the oxidation temperature. The samples prepared on silicon substrate indicate higher surface roughness than those prepared using quartz substrate. The band gap energy of the films elevated by increasing the oxidation temperature from 400 to 600 C, and then decreased by further increasing the annealing temperature to 800 C. The photoluminescence (PL) spectra of the films confirmed the emission due to exciton recombination related to near band edge emission (NBE) and emission due to defects.