Mikio Aramata

Polysilanes as conducting material producers and their application to metal pattern formation by UV light and electroless metallization

This paper describes a novel method for the deposition of gold, silver and palladium colloids on polysilane films by reducing the corresponding metal salt dissolved in alcohol without the use of any other reductants, and an application of the methodology to the pattern formation of copper and nickel metal by palladium-catalyzed electroless metallization on the surface of poly(methylphenylsilane) film, in combination with UV light lithography at 254 nm without the use of any other photoresists.

Effects of dopants and polymer structures on electrical conductivity of organosilicon polymers

Abstract A series of organosilicon polymers comprising disilanylene-phenylene, disilanylene-ethynylene and disilanylene-(bisethynylene-phenylene) chains carrying dibutyl or phenyl and methyl groups as side chains, and polysilanes carrying alkyl, aromatic or heteroaromatic side chains were synthesized. The electrical conductivities of their polymers doped with electron acceptors such as I 2 , FeCl 3 and SbF 5 were measured by using vapor-phase doping. The electrical conductivities of organosilicon polymers doped with I 2 showed a good correlation with the ionization potentials of the original polymers. In contrast, in the case of SbF 5 doping, the degradation of polymers occurred and every polymer gave the same order of conductivity, 10 −4 −10 −3 S/cm. The polymers carrying heteroaromatic substituents gave the higher conductivity by doping with I 2 , while in the case of the polymers carrying phenyl groups, the conductivity was enhanced by doping with FeCl 3 .

Electrical conductivity of organosilicon polymers II: Synthesis and electrical conductivities of iodine-doped polysilanes containing amino groups

Abstract A series of polysilanes containing an N,N -dimethylaminophenyl group and N -pyrrolyalkyl group as in the side chain were prepared by the Wurtz coupling polymerization. The polymerization of N -pyrrolylbutyl or N -pyrrolylhexyl-substituted dichlorosilane with sodium gave successfully the polysilanes with higher molecular weight than 10 5 . The electrical conductivities of I 2 -doped polysilanes were dependent on the chemical structure of the amino side chain. Moreover, by use of excess iodine, the conductivity of the polymer was enhanced. The electrical conductivity of poly[bis(6-( N -pyrrolyl)hexyl]silane] ( 7a ) increased to a maximum value of 8 × 10 −2 S/cm.

Photoelectric properties of organic polysilane containing carbazolyl side groups

The photoelectric properties of a series of N-carbazolyl-substituted silane copolymers have been studied by optical absorption, photoluminescence, and time-of-flight transient photocurrent measurements. It is found in N-carbazolyl-substituted silane copolymers that the optical absorption and the photoluminescence bands of the carbazolyl side groups, superimposed on those of the Si backbones, are observed in the blue to ultraviolet spectrum region. The hole drift mobilities of the copolymers are essentially the same as those of polymethylphenylsilane (PMePhSi) and are higher than those of poly(N-vinylcarbazole), and the photocarrier generation efficiencies of the copolymers are higher than those of PMePhSi. These results indicate that the photogenerated charge carriers on the carbazolyl side groups transfer to the Si backbones and then proceed through the Si backbones.

Electrical conductivity of organosilicon polymers III: Carrier mobility analysis of iodine-doped polysilane by hall effect measurement

Abstract The Hall effects of two different types of conducting polymers, poly[(6- N -pyrrolylhexyl)hexylsilane] (PSiPy) and poly( N -methylpyrrole) (PMePy) have been studied. Both of the polymers showed electrical conductivity orders of 10 −2 S/cm by I 2 doping. The polysilane, PSiPy, which is a σ-conjugated polymer, has a positive Hall coefficient and the absolute value of carrier mobility is higher by three orders of magnitude than that of the polypyrrole, PMePy, although the conductivities of both polymers are of the same order.

Mobility-Lifetime Products in N-Carbazolyl-Substituted Polysilanes

Mobility-lifetime products, µτ, of N-carbazolyl-substituted silane co- and homopolymers have been studied by means of photo-induced discharge measurements. With increasing concentration of N-carbazolyl groups, the µτ product is abruptly decreased at a certain concentration of N-carbazolyl groups. The result is consistent with our earlier finding that the hole transit was unobservable above the concentration in the time-of-flight measurements. The origin of the decrease in the µτ product is discussed.