Although Si and Mg impurities are essential elements for n and p type GaN, unintentional incorporation into
InGaN-multiple quantum wells (MQWs) seriously affects the optical property of LEDs. Si doping in MQWs obstructs
the hole carrier transport and induces the dead quantum wells (QWs) of MQWs. Also, Mg impurity diffusion from p-
GaN into MQWs degrades the radiative recombination rate of the QWs placed near Mg doped p-GaN layer. In this paper,
the effects of Si and Mg impurities on the optical property were systematically investigated.
Organic electronics open new fields of applications requiring large-area coverage, structural flexibility, low-temperature
and low-cost processing. A key for this technology is access to suitable materials. Progress in conducting and
semiconducting materials for organic electronics will be reported. Highly conductive PEDOT-grades have been
developed for high resolution printing. Linear oligomeric and star shaped oligothiophenes will be discussed. These
materials show outstanding carge carrier mobility and environmental stability when deposited from vacuum deposition.
After fine tuning the deposition parameter by ink jet printing we also obtained transistors with excellent properties. The
concept of "flexible core" star shaped oligothiophenes will be discussion which might be a way to combine both, high
charge carrier and wet processing.
As a result of intensive research on polymer light-emitting diodes (PLEDs) for the last several years, the device
performances have been remarkably improved. Recently, several researchers reported on a PLEDs with an interlayer
between poly(3,4-ethylenedioxythiophene)-poly-(styrenesulfonate) (PEDOT:PSS) and an emissive polymer. It improved
the device efficiency as well as the device lifetime. The role of the interlayer is to block the electron from back diffusion
to PEDOT:PSS and/or to reduce luminescence quenching at the PEDOT:PSS interface.
We studied the improvement of the PLED by inserting an octadecyltrichlorosilane (OTS) as the interlayer between
PEDOT:PSS and the emissive layer. The OTS was treated on PEDOT:PSS through the self-assembled monolayer (SAM)
process. It improved the device efficiency of the PLED from 3.86 to 4.76 cd/A, and increased the operation lifetime from
270 to 340 minute comparing the non-OTS treated PLED with the OTS treated PLED for 10 min. In blue PLED,
inserting the OTS layer between blue polymer and PEDOT:PSS is promoted hole injection from an anode. Therefore, the
device efficiency is improved, which appears to be due to the increase of balanced recombination as a result of the
accumulated electrons near the interface between emissive layer and PEDOT:PSS.
The Ni-silicide of a sheet resistance of 7 (Omega) /(open square) can be formed at 230 degree(s)C on n+ a-Si:H and thus can be applied to gate and source/drain contacts for high performance TFTs. Because of its low resistance it is possible to make a self-alignment between gate and source/drain, which lead to a coplanar a-Si:H TFT having a low parasitic capacitance between them. The NiSi2 precipitates can be formed on a-Si:H at around 350 degree(s)C and needlelike Si crystallites are grown as a result of the migration of the NiSi2 precipitates though a-Si:H network. Amorphous silicon can be crystallized at 500 degree(s)C in 10 minutes in a modest electric field. The low temperature poly-Si TFT with a field effect mobility of 120 cm2/Vs has been demonstrated using the low temperature poly-Si.
This paper presents the process and experimental results for the improved silicon-to-glass bonding using silicon direct bonding (SDB) followed by anodic bonding. The initial bonding between glass and silicon was caused by the hydrophilic surfaces of silicon-glass ensemble using SDB method. Then the initially bonded specimen had to be strongly bonded by anodic bonding process. The effects of the bonding process parameters on the interface energy were investigated as functions of the bonding temperature and voltage. We found that the specimen which was bonded using SDB process followed by anodic bonding process had higher interface energy than one using anodic bonding process only. The main factor contributing to the higher interface energy in the glass-to-silicon assemble bonded by SDB followed by anodic bonding was investigated by secondary ion mass spectroscopy analysis.