The temperature had an important influence in the life time of light emitting diodes (LED). In this
study, we fabricated the ceramic porous films, by vacuum sputtering, soldered the LED lamps to
enhance both of the heat transfer and heat dissipation. In our samples, the ceramic enables transfer the
heat from electric device to the aluminum plate quickly and the porous increase the quality of the
thermal dissipation between the PCB and aluminum plate, as compared to the industrial processing.
The ceramic films were characterized by several subsequent analyses, especially the measurement of
real work temperature. The X-Ray diffraction (XRD) diagram analysis reveals those ceramic phases
were successfully grown onto the individual substrate. The morphology of ceramic films was
investigated by the atomic force microscopy (AFM). The results show porous film fabricated by
vacuum sputtering has high sheet resistivity, critical load, and thermal conduction to the purpose. At
the same time, it had transferred heat and limited work temperature, ~80°C, of LED successfully.
The amplitude of terahertz radiation (THz) from a series of oxide films on GaAs was measured by time resolved THz
emission system. The barrier heights and the densities of the interfacial states are determined from the PR intensity as a
function of the pump power density. The oxide-GaAs structures fabricated by in situ molecular beam epitaxy exhibit low
interfacial state densities in the range of 1011 cm-2. It is found that the amplitude of THz radiation from Al2O3-,
Ga2O3-,
and Ga2O3(Gd2O3)-GaAs structures are increases with interfacial electric field. The reason is that the electric field is
lower than the "critical electric field", the amplitude is proportional to the product of the electric field and the number of
photo-excited carriers. However, as the field higher than the critical electric field, sample of air-GaAs structure, the lower
THz amplitude was obtained due to the maximum drift velocity declines slightly as the field increases.
Room-temperature contactless electroreflectance (CER) was used to investigate the optical properties of a
N,N'-didecylperylene-3,4,9,10-tetracarboxylic diimide
(PTCDI-C10H21) thin-film sandwiched between indium tin oxide
and aluminum electrodes (Al/PTCDI/ITO/glass substrate) under vacuum conditions. The electromodulated optical
responses of the Al/PTCDI/ITO/glass structures were characterized by various alternating current biases. The optical
transitions of PTCDI were perturbed by energy shifts of electronic states due to the Stark effect induced by the
modulated electric field. The modulated CER spectrum of PTCDI is strongly enhanced by performing first derivatives on
the absorption spectrum of PTCDI. The CER spectrum involves fundamental transitions, doping states, and Davydov
splitting. Moreover, the intensity of the field-induced transition peak of PTCDI increases with increasing CER
modulation voltage. The transition energies between the lowest unoccupied molecular orbital and highest occupied
molecular orbital of the Al/PTCDI/ITO system is obtained from the peak positions in the CER spectrum.
Room temperature photoreflectance (PR) was used to investigate the energy gaps transition, the surface state densities
and the surface barrier height of InxAlyGa1-x-yAs, in a series of epitaxial surface intrinsic-n+ structures with different Al
concentration. Features of Franz-Keldysh oscillations originating from the built-in electric field in the intrinsic top layer
were observed. Based on the thermionic emission theory and current-transport theory, the surface state density can be
determined from the square of maximum electric field as a function of various pump beam flux intensities.
The thermal conductivity has the important influence in quantum effect of light emitting diodes (LED)
especially in high brightness light emitting diodes (HB LED). One of the biggest challenges is efficient
heat transfer from PCB to aluminum plate when it base on printed circuit board (PCB). Because it
enables transfer the heat from electric device to the aluminum plate, which completely removes the
heat. In this study, alumina (Al2O3), alumina nitride (AlN) and zinc sulfide (ZnS) films soldered the
HB LED lamps to enhance the heat transfer. All of the films were fabricated onto 1070 aluminum
substrate by vacuum sputtering technology. The dielectric coatings were characterized by several
subsequent analyses, especially the measurement of thermal resistance. The X-Ray diffraction (XRD)
diagram analysis reveals three kinds of ceramic thin films were successfully grown on the individual
substrate. Moreover, the alumina nitride coating has low sheet resistivity, high hardness, high critical
load, and good thermal conduction, 200 W/m-K, as compared to those of Al2O3 and ZnS films.
Heat transfer has the important influence in quantum effect of light emitting diode (LED). In the
industrial processing, the quality of the thermal dissipation decides by the gumming technique between
the printed circuit board (PCB) and aluminum plate. Because it transfers the heat from electric device
to the aluminum plate which removes the heat. In this work, the alumina nitride (AlN) thin film
soldered the LED lamps to enhance the heat transfer. The films were fabricated onto 1070 aluminum
substrate by vacuum sputtering and plasma spraying technologies individually. The dielectric coatings
were characterized by several subsequent analyses, especially the real temperature measurement of
dielectric coating films. The X-Ray diffraction (XRD) diagram analysis reveals that ceramic phase can
successfully grow on the individual substrate. The studied results show that AlN thin film fabricated by
vacuum sputtering has low sheet resistivity, high hardness, high critical load, and good thermal
conduction (200 W/m-K); but, the same of coating fabricated by plasma spraying technology had the
best heat transfer as compared to the other samples.
Optical responses of a modulation doped lattice-matched InGaAs/InAlAs single quantum well structure
grown by gas source molecular beam epitaxy were characterized by photoreflectance PR at various
temperatures and depths. Two features corresponding to the ground state transition coming from the
SQW and the band gap transition generated from the buffer layer are observed in the PR spectra and
agree with those calculated theoretically. The optical transitions were perturbed by the energy shifts of
the electronic states due to Stark effect induced by the doped result. The values of the Varshni
coefficients of InGaAs/InAlAs were obtained from the relation between the exciton transition energy
and the temperature. The built-in electric field could be determined and located from a series of PR
spectra by sequential etching processes. The results suggest that a built-in electric field exists at the
buffer/substrate interface.
Thermal management has the important influence in quantum effect of light emitting diodes (LED)
based on printed circuit board (PCB). In the industrial processing, the quality of the thermal
dissipation is decided by the gumming technique between the PCB and aluminum plate. Because it
transfers the heat from electric device to the aluminum plate, which completely removes the heat. In
this study, a superior method, alumina thin films, soldered the LED lamps to enhance the heat transfer.
The films were fabricated onto 1070 aluminum alloy substrate by plasma spraying, vacuum sputtering
and electric plating technologies. The dielectric coatings were characterized by several subsequent
analyses, especially the measurement of thermal resistance. The X-Ray diffraction (XRD) diagram
analysis reveals that alumina phases were successfully grown on the individual substrate. Compared to
alumina coating fabricated by plasma spraying and electric plating technologies, vacuum sputtering
creates low sheet resistivity, high hardness, high critical load, and good thermal conduction of 119
W/m-K.
The production of CuInGaSe2 (CIGS) solar cell is based on vacuum processes, which requires a high manufacturing
temperature and high cost. Our result show a simple method has been developed to prepare the silica substrates of CIGS
solar cell. It's synthesized by sol-gel process from tetraethylorthosilicate (TEOS), methanol (CH3OH) and pure water (both ion-exchange and distillation) in the presence of ammonia as catalyst. The preparation procedure was elaborated as
the flexible sequence to control chemical composition and properties of the particles in sol-gel-derived silica substrate.
The morphology, particle size, and size distribution of CIGS substrate were characterized with dynamic light scattering
(DLS) and atomic force microscopy (AFM). The results of AFM morphology and statistic evidence we find an easy way,
non-vacuum and low temperature processes, to successfully prepare the CIGS solar cell substrates with surface roughness below 3 nm. It is powerful the advance study in low cost solar cell.
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