Papers by Keyword: Electroluminescence

Abstract: This work explores the role of implantation depth in suppressing bipolar degradation of 4H-SiC PiN diodes through proton implantation. Targeting depths aligned with active basal plane dislocations (BPDs) effectively reduces stacking-fault expansion, as confirmed by electroluminescence imaging [1,2]. From these observations, we quantified the effective range of suppression in both depth and safe operating current density. Room-temperature proton implantation (170keV, 1×10¹⁶ cm^-2) into the buffer reduced forward-voltage drift ΔV_F by 97% at 600A/cm². The implanted diode extended the safe operating current range to 1300A/cm², ~200A/cm² higher than the reference, confirming effective suppression of bipolar degradation. Once the suppression barrier, defined as a critical excess hole density threshold, was exceeded, the proton-implanted diode exhibited explosive basal plane dislocation activity, leading to the formation of multiple bar-shaped stacking faults. These active BPDs are located deeper than the proton-implant tail, at a depth of around 11.4µm; however, the threshold hole density required for their activation remains approximately the same (~ 4×10¹⁶ cm^-3) [3].

Abstract: In this paper, a method for suppressing bipolar degradation through proton implantation was investigated. Previous work suggests implantation applied to the full thickness of the epi layer, which results in unwanted defects leading to a deterioration in performance. In this work, proton implantation to the buffer layer was successful in reducing the forward-voltage drift ΔV_F of the fabricated SiC PiN diode by 85% at a current density of 800A/cm², when applying room temperature (RT) proton irradiation at a dose of 1×10¹⁶ cm^-2. Irradiation solely to the buffer layer keeps the deterioration of forward current performance to a minimum, while the fabricated SiC PiN diodes are more robust against bipolar degradation at higher current density. In addition, RT proton irradiated PiN diodes show full recovery from their bipolar degraded characteristics within 2.5 h of annealing at 350 °C under vacuum. This indicates proton irradiation alters the crystal structure for the stacking fault (SF) to “shrink” back with ease to their initial basal plane dislocations (BPD) state.

Abstract: To reach the theoretical performance limit of 4HSiCMOSFETs the SiC/SiO2interfacedefects along the inversion channel need to be fully identified in order to be avoided. We employa measurement technique that allows to observe energetically resolved trap states at the SiC/SiO2 interface by measuring the electrolumiscence of a gate pulsed MOSFET. The spectra are recorded at room and cryogenic temperatures with a spectrometer and two different amplitudes of the gate pulse. Comparison of the results to literature allows for identification of the L1 line of the D1 center with an energy of 2.9 eV and suggests donoracceptorpair recombination or Z1/2 to be responsible for the emission around 2.5 eV. Ionization energies of PbC and related vacancy centers determined via ab initio calculations show similar results as the experimental data and provide a possible classification of the trap level around 1.8 eV.

Abstract: On a film of aluminum oxide (Al₂O₃) formed by electrolytic oxidation in distilled water (DW), the growth, transformation of its nanoporous structure, and the generation of electroluminescence (EL) in ketones and related compounds containing carbonyl groups were studied. For those contributing to the brightest EL – acetylacetone and methylpyrrolidone, it was found that the processes described in these electrolytes proceed with the highest intensity. Under the same electrolytes and conditions, similar processes, but with a lower intensity, proceed for A₂O₃ formed on pure aluminum. It was found that, with the external voltage, thermodynamic and geometrical parameters of the electrolytic system being constant, the brightness characteristics of the EL of the anodic Al₂O₃ are influenced by its structural organization and the electrophysical characteristics of the electrolyte surrounding the oxide film, which is proposed to be arbitrarily called “nonelectrolysis” because electrolysis products are not revealed in it.

Abstract: With the development of electroluminescence application on display, the traditional structures are very classic and often monopolized by special companies in the world. Nowadays, technologies have developed very quickly so that lots of countries focus on the nanoink and substrate material. In fact, the process of producing various flexo screen display can be applied into the variable sized consumer packages by other conductive and phosphor printing material. In this paper, two different sequences of printing will be introduced to compare the advanced style on new structure design. This study also attempts to show the referable ways on materials to help optimize ways in electroluminescence application.

Abstract: We demonstrated that silicon vacancy (V_Si) can be created in SiC pn junction diode by proton beam writing (PBW) without degradation of the diode performance. The V_Si showed the same specific emission for both optically and electrically excitation, which suggests that electrically controllable V_Si was created. In addition, optically detected magnetic resonance (ODMR) signal was successfully detected from optically excited V_Si at room temperature. This result suggests that V_Si introduced into the device by PBW still maintain spin manipulating capability, which is an important step toward realizing SiC devices internally equipped with a V_Si-based quantum sensor.

Abstract: La₂Ti₂O₇:Pr powder was prepared by a solid-state reaction method. Photoluminescence due to f-f transitions of Pr³⁺ was induced by band-gap excitation of La₂Ti₂O₇. La₂Ti₂O₇:Pr thin film was prepared by sol-gel and spin-coating methods. The thin film showed visible electroluminescence due to f-f transition of Pr³⁺ by applying ac voltages.

Abstract: Core/shell/shell of CdSe/CdTe/CdS QDs were prepared by chemical reaction and used to fabricate hybrid quantum organic light emitting devices (QDOLEDs). QDOLEDs were made-up using layers of ITO/PEDOT: PMMA/QDs/Alq₃ and ITO/PEDOT: PMMA/QDs/Alq₃/TPBi devices which prepared by phase segregation method. The hybrid white light emitting devices consists, of four-layers deposited successively on the ITO glass substrate; the first layer was of Poly(3,4-ethylenedioxythiophene) (PEDOT) polymer mixed with polymethyl methacrylate (PMMA) polymers. The second layer was QDs and the third layer was tris (8-hydroxyquinoline) aluminium (Alq₃) while the fourth layer was 1,3,5-tri(phenyl-2-benzimi-dazolyl)-benzene (TPBi) electron extraction layer (EEL)The results of the optical properties show that the prepared QDs were nanocrystalline with defects formation. The produced white light has suitable efficiency by confinement effect which creates the energy gap larger, so that the aim of the light sites are toward the center of white light color.The quantum dots organic light emitting devices (QDOLEDs) were characterized by electroluminescence (EL) at room temperature. Current-voltage (I-V) characteristics indicate that the output current is good compared to the few voltages ( 4-6 V) used which gives acceptable results to get a generation of white light. The emissions affecting this white luminescence were detected depending on the chromaticity coordinates (CIE 1931). The correlated color temperature (CCT) was found to be about 6300 and 5290 K. Fabrication of QDLEDs from semiconductors material (CdSe/CdTe/CdS core/shell/shell QDs) with hole injection organic polymer (PEDOT) and electron injection from organic polymer molecules (TPBi) was successful in white light production.

Abstract: This paper presents OBIC measurements performed at near breakdown voltage on two devices with different JTE doses. Overcurrent has been measured either at the JTE periphery or at the P⁺ border. Such overcurrent is present due to the electric field enhancement near the breakdown voltage. This hypothesis is proved by the electroluminescence. TCAD simulation of two different JTE doses yielded similar results to the OBIC measurements.

Abstract: Nanocrystalline cadmium sulfide/Polyvinyl alcohol composite films were prepared by chemical route using Cadmium acetate and hydrogen sulfide gas as cadmium and sulfur source respectively. Poly vinyl Alcohal (PVA) used as polymer matrix. The initially loading of cadmium precursor influences the size as well as photoluminescence and electroluminescence properties of the Composite film. The films were characterized by X Ray Diffraction (XRD), Atomic Force Microscopy (AFM) and UV-Visible Absorption spectra. The X-ray Diffraction result showed that CdS nanocrystals embedded in polymer matrix were in a zinc blend cubic structure. The UV-Visible absorption spectra of composite film reveal the blue shift in the band gap energy with respect to CdS bulk (2.42eV) material owing to quantum confinement effect. The Photoluminescence emission spectra show the green light emission at 510 nm arising from the defects states due to excess of cadmium or sulfur anion vacancies. Electroluminescence study indicates enhanced emission with low turn on voltage for higher loading of cadmium in polymer matrix due to increased oscillator strength. When higher electric field is applied, light emission start due to acceleration collision mechanism by charge carries inside the composite film.