Papers by Keyword: EL

Abstract: In this paper, we improved the home-made EL experimental set-up, have increased the function of TSC, enable the joint measurement of EL and TSC to measure the trap of shallow and deep. It is significant to study material properties. through the Labview8.6 software programming, the data of temperature and current could be collected, then we can get the curve that the current changes with temperature, it is the TSC curve. Experiment result proved the reliability of laboratory equipment.

Abstract: In this paper we combine LBIC and EL measurements of commercially multi-crystalline silicon solar cells, in order to obtain detailed information about the electrical activity around defect areas. This integrated analysis is suitable for the study of different crystal defects at both micrometric and full wafer scale. In particular, the electrical activity of some defect areas is studied in detail by means of highly spatially-resolved LBIC maps, showing important differences in their behaviours. A discussion about the origin of these differences is presented.

Abstract: In this paper, ZnO Nano-particles is embedded in polyimide, and physical and chemical properties of polyimide/ZnO composite materials have been studied. It is found that different ZnO content will cause UV absorption edge blue shift, and EL tests show that electricity aging and pre-breakdown have changed. For PI/ZnO(1%) and PI/ZnO(2%) composite materials, Electricity aging is at 1.4Mv/cm and 1.5Mv/cm, Pre-breakdown field is at 1.9Mv/cm and 1.8Mv/cm, respectively. In addition, there are emission peaks at 442.8nm, 514.2nm, 609.4nm in the EL spectrum of the PI/ZnO (1%) films and 538nm, 633.2nm of PI/ZnO(2%) films, which indicates that some defects in this area.

Abstract: For the growth of Electroluminescent (EL) device market, the attention of many researchers is centered on improving the properties such as brightness, power consumption, device reliability, etc. The powder EL device is one of solutions for the easy mass production, the simplification of structure, and low cost. Although the powder process is the solution, that has the problem with the poor brightness than the film process. So, we focused on increasing the brightness of powder EL device. The emissive layer was made up the composites adding metal oxide nanopowder such as TiO2 and ZnO to powder phosphors. As the data of previous researcher, the TiO2 and ZnO had the different dominating traps by photovoltage measure, that is, TiO2 show hole traps, ZnO show electron traps [1]. The brightness of powder EL device proportions to the high electricfield formation. The TiO2 or ZnO in the powder phosphor composite can help the emission that may be advantageous to form high electricfield at low voltage. The EL devices with green ZnS phosphor were fabricated using spin coating method. The effect of TiO2 and ZnO on the luminescent property of EL device was investigated. The brightness was obtained as applied driving voltage at 400 Hz and frequency variation at 50 V.

Abstract: The electrical properties of n+-GaN/p+-SiC heterojunction diodes have been investigated by varying the acceptor concentration of p+-SiC epilayers (Na) and polytype of SiC (4H- and 6H-SiC). The current-voltage (I-V) characteristics of diodes with Na ~ 1x1019 cm-3 were dominated by tunneling-assisted current. The diodes with Na ~ 1x1018 cm-3 exhibit excellent characteristics and 6H-SiC may be a better choice from a view point of electron injection into p-SiC base. Compared to previous investigations (Na<1016cm-3), we could obtain good rectification with p-SiC doped to two-order-of-magnitude higher acceptor concentration.

Abstract: Characterization of n+-GaN/p−-SiC and n+-GaN/p+-SiC heterojunctions as well as fabrication of GaN/SiC heterojunction bipolar transistors (HBTs) using these heterojunctions is presented. The electroluminescence spectrum from n+-GaN/p+-SiC heterojunction diodes under forward bias clearly indicates electron injection from n+-GaN into p+-SiC. HBTs consisting of n+-GaN emitter /p+-SiC base/n−-SiC collector/n+-SiC substrate have been fabricated. Although clear common-base properties were obtained, the current gain was very low (10-4). SiC homojunction bipolar junction transistors (BJT) using the same base-collector junction exhibited a current gain value of 0.5, suggesting the low current gain of GaN/SiC HBTs originates from low emitter efficiency.

Abstract: Electroluminescence of B and P implanted samples has been studied. P implantation is found to have a similar effect on light emission as B implant. The band-to-band (BB) luminescence of P implanted diodes is observed to increase by more than one order of magnitude upon rising the temperature and an internal efficiency of 2 % has been reached at 300 K. An efficiency larger than 5% seems to be reachable. The strong BB line emission at 1.1 &m is attributed to high bulk SRH lifetime. The BB line escapes from the substrate below the p-n junction. It is not due to the implantation-related defects/dislocations. The luminescence spectrum can be tailored to achieve dominance of the dislocation-related D1 line at about 1.5 &m. It is observed that a regular periodic dislocation network, formed by Si wafer direct bonding with a specific misorientation, exhibits even at 300 K only D1 photoluminescence. Such a dislocation network is believed to be a serious candidate to gain an efficient Si-based light emitter.