THE ROLE OF OLED DEVICES IN THE DEVELOPMENT OF SMART CITIES

In the course of the last few years, interest in the development of smart cities and progress of smart buildings has increased significantly. This development has been significantly increased due to the development of new technologies, innovative functional materials, electronic components and other products. At the same time, it is imperative to use those products that contribute to the preservation of the environment, and above all to energy saving. Thus, new technologies are becoming increasingly attractive, such as the one based on OLED (Organic Light Emitting Diode) technology, which is used in the production of mobile phones, tablet computers, other devices, as well as light sources. Although this technology has been generally known for more than half a century, commercial application of OLED components was not possible due to insufficient efficiency of products based on it. However, the continuous improvement of characteristics and efficiency enabled their more significant application in the past few years. The aim of this work is to provide adequate information about the possibilities of applying some innovative technologies in the planning and development of smart cities. Especially, becoming more familiar with the basic properties and application possibilities of OLED devices can lead to the life quality improvements of city spaces users

The comparison of gamma-radiation and electrical stress influences on oxide and interface defects in power VDMOSFET

The behaviour of oxide and interface defects in n-channel power vertical double-diffused metal-oxide-semiconductor field-effect transistors, firstly degraded by the gamma-irradiation and electric field and subsequently recovered and annealed, is presented. By analyzing the transfer characteristic shifts, the changes of threshold voltage and underlying changes of gate oxide and interface trap densities during the stress (recovery, annealing) of investigated devices, it is shown that these two types of stress influence differently on the gate oxide and the SiO2-Si interface. [Projekat Ministarstva nauke Republike Srbije, br. OI171026

EFFECTS OF PULSED NEGATIVE BIAS TEMPERATURE STRESSING IN P-CHANNEL POWER VDMOSFETS

Our recent research of the effects of pulsed bias NBT stressing in p-channel power VDMOSFETs is reviewed in this paper. The reduced degradation normally observed under the pulsed stress bias conditions is discussed in terms of the dynamic recovery effects, which are further assesed by varying the duty cycle ratio and frequency of the pulsed stress voltage. The results are analysed in terms of the effects on device lifetime as well. A tendency of stress induced degradation to decrease with lowering the duty cycle and/or increasing the frequency of the pulsed stress voltage, which leads to the increase in device lifetime, is explained in terms of enhanced dynamic recovery effects

NBT STRESS AND RADIATION RELATED DEGRADATION AND UNDERLYING MECHANISMS IN POWER VDMOSFETS

In this paper we provide an overview of instabilities observed in commercial power VDMOSFETs subjected to irradiation, NBT stress, and to consecutive exposure to them. The results have indicated that irradiation of previously NBT stressed devices leads to additional threshold voltage shift, while NBT stress effects in previously irradiated devices depend on the gate bias applied during irradiation and on the total dose received. This points to the importance of the order of applied stresses, indicating that for proper insight into the prediction of device behaviour not only harsh conditions, but also the order of exposure have to be considered. It has also been shown that changes in the densities of oxide trapped charge and interface traps during spontaneous recovery after each of applied stresses can be significant, thus leading to additional instability, even though the threshold voltage seems to remain stable, pointing to the need for clarifying the responsible mechanisms

Response of Commercial P-Channel Power VDMOS Transistors to Ionizing Irradiation and Bias Temperature Stress

n this paper, the e®ects of successively applied static/pulsed negative bias temperature (NBT)stress and irradiation on commercial p-channel power vertical double-di®used metal-oxidesemiconductor (VDMOS) transistors are investigated. To further illustrate the impacts of thesestresses on the power devices, the relative contributions of gate oxide charge (Not) and interfacetraps (Nit) to threshold voltage shifts are shown and studied. It was shown that when irradi-ation without gate voltage is used, the duration of the pre-irradiation static NBT stress has aslightly larger e®ect on the radiation response of power VDMOS transistors. Regarding the factthat the investigated components are more likely to function in the dynamic mode than thestatic mode in practice, additional analysis was focused on the results obtained during thepulsed NBT stress after irradiation. For the components subjected to the pulsed NBT stressafter the irradiation, the e®ects ofNotneutralization andNitpassivation (usually related toannealing) are more enhanced than the components subjected to the static NBT stress, becauseonly a high temperature is applied during the pulse-o® state. It was observed that in devicespreviously irradiated with gate voltage applied, the decrease of threshold voltage shift is sig-ni ̄cantly greater during the pulsed NBT stress than during the static NBT stres

Radiation Tolerance and Charge Trapping Enhancement of ALD HfO2/Al2O3 Nanolaminated Dielectrics

High-k dielectric stacks are regarded as a promising information storage media in the Charge Trapping Non-Volatile Memories, which are the most viable alternative to the standard floating gate memory technology. The implementation of high-k materials in real devices requires (among the other investigations) estimation of their radiation hardness. Here we report the effect of gamma radiation (60Co source, doses of 10 and 10 kGy) on dielectric properties, memory windows, leakage currents and retention characteristics of nanolaminated HfO2/Al2O3 stacks obtained by atomic layer deposition and its relationship with post-deposition annealing in oxygen and nitrogen ambient. The results reveal that depending on the dose, either increase or reduction of all kinds of electrically active defects (i.e., initial oxide charge, fast and slow interface states) can be observed. Radiation generates oxide charges with a different sign in O2 and N2 annealed stacks. The results clearly demonstrate a substantial increase in memory windows of the as-grown and oxygen treated stacks resulting from enhancement of the electron trapping. The leakage currents and the retention times of O2 annealed stacks are not deteriorated by irradiation, hence these stacks have high radiation tolerance

Railway vehicles diesel engine and turbo transmission optimal coupling

Fulfilment of the optimal traction conditions (primarily the maximum tractive force and efficiency coefficient) of a diesel motor train depends on proper coupling of the diesel engine and turbo transmission (torque converter). During the construction and installation of new engines and transmissions, or during diesel engine replacement, it is necessary to adjust the operational characteristics of the engine. In this paper, the methodology outlined was developed and applied in the reconstruction project of the diesel motor train produced by Macosa, Spain, and used by the Macedonian Railways. Reconstruction has included replacement of the diesel engine, the replacement of the complete cooling system for the diesel engine, the turbo transmission and the axle transmitter. To verify the reconstruction, power system tests were carried out on the test rig, including: (a) diesel engine and turbo transmission coupling testing, (b) determination of turbo transmission output traction parameters, an

Railway vehicles diesel engine and turbo transmission optimal coupling

Fulfilment of the optimal traction conditions (primarily the maximum tractive force and efficiency coefficient) of a diesel motor train depends on proper coupling of the diesel engine and turbo transmission (torque converter). During the construction and installation of new engines and transmissions, or during diesel engine replacement, it is necessary to adjust the operational characteristics of the engine. In this paper, the methodology outlined was developed and applied in the reconstruction project of the diesel motor train produced by Macosa, Spain, and used by the Macedonian Railways. Reconstruction has included replacement of the diesel engine, the replacement of the complete cooling system for the diesel engine, the turbo transmission and the axle transmitter. To verify the reconstruction, power system tests were carried out on the test rig, including: (a) diesel engine and turbo transmission coupling testing, (b) determination of turbo transmission output traction parameters, an

Feasibility of applying an electrically programmable floating-gate MOS transistor in radiation dosimetry

In this paper we investigated the feasibility of using a commercial programmable floating-gate MOS transistor (EPAD) as a radiation dosimeter. The results show that EPAD with zero bias have the sensitivity of 9.2 mV/Gy and low fading. EPADs with a higher initial threshold voltage show very good linearity with the radiation dose. After its annealing at 70 °C there is a visible recovery of transfer characteristics due to a parasitic parallel resistive path that occurs during irradiation. Apart from that, the threshold voltage is slightly recovered. The programming time of an EPAD increases with the absorbed dose and depends on gate biasing during irradiation. © 2019 IEEE.31st IEEE International Conference on Microelectronics, MIEL 2019; 16-18. September 2019; Conference Code:15391