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and Cl, gas pressure are investigated. GaAs(111)A occurs. Surface morphol- techniques contribute to the problem. Etching profiles and surface morphol- ogy is better than that of conventional Laser light is monochromatic and ogy are also observed. Xe/Hg lamp etching in which etchant and UV light intense, interferes with each other, power, etchant supply time, and sub- irradiation are supplied simultaneously. and can be pulsed and focused to a strate temperature are fixed through
wavelength order spot. Furthermore, all experiments at 0.19 W/cm2, 1 second, Although no self-limiting process it is possible to follow molecular energyand 10 °C, respectively.
was obtained in the current DPE sys- relaxation processes and chemical reac
tem, the etched depth can be controlled tions in small dimensions with pico(1) UV irradiation time dependence: by sequence time alone if the etchant second time resolution. This means we The Cl, gas pressure was 1 x 10* Torr pressure is controlled precisely. Crys- have an “eye” for observing chemistry and evacuation time was 12 seconds. tallographic atomic-layer-controlled micrometer dimensions. By utilizing Etching rate is saturated for an irradi- etching like DPE is expected to play an the optical pressure of a laser beam, we ation time of more than 20 seconds. important role in the fabrication of can choose a single particle in a disThis means that 20 seconds of irradia. ISIT or quantum effect devices. persed solution and manipulate and fix tion is enough to promotesurface reac
the particle at a certain spacial position of adsorbed etchant and desorp- MASUHARA MICROPHOTO- tion. The surface of an individual partion of etching products.
CONVERSION PROJECT: ticle is photochemically modified, and
a small area of the surface is fabricated. (2) Cl gas evacuation time depen- PHOTON TECHNIQUES We can say we have a potential "hand" dence: The Cl gas pressure was
for microchemistry. 1x 10+ Torr and UV irradiation time Project Director: Hiroshi Masuhara In general, a reaction field is intrinwas 20 seconds. The etching rate has a
sically important to control chemical plateau region with the etchant Microtechnology is now recognized reactions; therefore, it is strongly sugevacuation time from 3 to 12 seconds. as a general trend and affords various gested to prepare a micrometer size This indicates that the amount of possibilities in science, as microelec- small reaction field. This is now possiadsorbed etchant is constant during tronics, microoptics, microsurgery, ble by introducing various microfabrithis time. In the region less than micromachine, and so on. When a reac- cation techniques: laser ablation, micro3 seconds, the residual etchant probably tion vessel is reduced to a micrometer- lithography, scanning electrochemical contributes to the etching. In the region order dimension, the contribution of microscope, chemical vapor deposition, more than 12 seconds, the etchant surface and interface to the chemical and microelectrochemistry. The surdoesn't seem to adsorb in the same and physical properties of solution face of semiconductors, metals, amount any more and probably desorbs increases. As an example, the viscosity polymeric materials, etc. is physically from the substrate gradually.
of a liquid increases and intermolecu- and chemically modified. Spatial micro
lar interactions in solution could be patterns can be arbitrarily introduced (3) Cl2 pressure dependence: The influenced to a greater extent by reduc- onto a small area of the material's surUV irradiation time was 6 seconds and ing the size of a reaction vessel. Clearly, face. This means we have a “field" for the etchant evacuation time was
chemistry in micrometer dimensions is microchemistry. 6 seconds. For these conditions, no sat- extremely important and worthy to be Thus, chemical reactions and mateurated region is obtained. This means studied. Nevertheless, microchemistry rials conversion in micrometer dimenthat there is no self-limiting of adsorp- and chemical microengineering have sions are made possible by photon tion. Therefore, the etchant gas pres- never been discussed as one of the techniques and very wide research fields sure must be controlled precisely in microtechnologies. We expect explor- have been opened. Scientific and techorder to control the etching rate. The atory research on chemical and mate- nological products are classified into gas injection time and substrate tem- rials conversion in micrometer size the following three subjects. The first perature, however, should be consid- dimensions to be promising as a new concerns the development of spaceered for the probability of the self- science and technology.
and time-resolved spectroscopy and limiting process.
To realize the idea, a variety of elucidation of micrometer size effects never been explored, such studies are elucidating structure and dynamics in material's surface in solution. A fluorean extremely interesting subject. the surface/interface layers of solids scence micropattern is produced on an
methods to prepare minute reaction upon physical and chemical dynamics, (4) Etching profile and surface sites as well as to measure and control which can be revealed by microspecmorphology: DPE exhibits crystallo- reactions should be developed. Recent troscopy. Although molecular relaxagraphic etching because no etching of progress in laser and microfabrication tion phenomena and chemical reac
tions in micrometer small volumes have
Secondly, we will study the physical and liquids (Ref 10). It has been clari- ionic conducting polymer film. The film and chemical properties of a single fied that the properties in the surface/ contains a fluorescent dye and a individual particle that is trapped by interface layers with thickness of quencher, and the latter was decomoptical pressure, elucidate mechanics 0.1 micron were different from those posed electrochemically along a locus of particle motions and intraparticle in the bulk (Ref 11). Analogous results of an SECM tip. Therefore, the scanned interactions, and construct micrometer were obtained for photophysical prop- area emits the letter “M.” This indistructures by photochemical adhesion erties of molecules in alcohols and water. cates that the SECM can act as a new of particles. This is a novel subject and To measure transient absorption method for electrochemical modificais called the chemistry of a single micro- spectra and their rise/decay dynamics, tion of a small area on a material's particle. we have developed two types of new
surface. The third is microfabrication and spectroscopic techniques where a sub- Microelectrodes were fabricated by microfunctionalization of polymeric picosecond (ps) white continuum was microlithographic techniques and used materials by laser and microfabrica- used as the monitoring light (Ref 12). for pH sensing and photoelectrochemtion techniques. Preparation of a series One is to introduce sub-ps excitation ical reactions (Ref 13). Photodecomof micrometer reaction sites with dif- and monitoring pulses into microscope position of water was performed on ferent chemical and physical functions optics, which enables us to obtain absorp- microarray electrodes of Pt and Tioz and their spatial arrangement will afford tion spectra of a single microcrystal, a under a microscope. Spectral measurea new dynamic function. Toward our liquid droplet, and molecules in porous ments also have been performed to final goal, we are exploring a prototype glasses. The other is a new technique elucidate the photoelectrochemical of integrated microchemical systems, called sub-ps transient grating spec- mechanism. utilizing our original techniques of troscopy. The excitation pulse forms a Micrometer patterns of polymermicrochemistry: "eye," "hand," and transient grating that diffracts the ized phthalocyanine derivatives were "field."
probing continuum. The diffraction prepared by developing a new techThe project consists of three groups efficiency as a function of wavelength nique called area-selective chemical dealing with laser spectroscopy, micro- of the probing continuum is related to vapor deposition. fabrication techniques, and reaction transient absorption spectra in the control. During these 3 years we have excited states of chemical intermedi- 3. Microconversion System Group presented 57 and 30 papers to domes- ates. The high sensitivity of the novel (Research Institute for Production tic and international symposia, respec- spectroscopic technique promises future Development, Kyoto). Characteristic tively, and presented a lot of reviews applications to study chemical reac- micrometer size effects upon chemical and invited lectures. Now 14 researchers tions in micrometer small dimensions. reactions are studied, and new methincluding 3 foreign scientists are working. In addition to these methods, a laser ods for controlling chemical reactions
manipulation-spectroscopy-reaction in small dimensions are developed. 1. Dynamic Microspectroscopy system has been developed.
Furthermore, the laser manipulationGroup (Kyoto Research Park Co. Ltd.,
spectroscopy-reaction system is applied Kyoto). A new class of spectroscopy for 2. Microchemical Function Group to reveal and control chemical reactions elucidating picosecond chemical pro- (Central Research Laboratories, and to construct microstructures for cesses in micrometer small dimensions Idemitsu Co. Ltd., Sodegaura). Using creating a prototype of a microchemical is being developed. A laser trapping various fabrication techniques, microm- factory. technique of microparticles is combined eter sites with chemical functions are Micrometer size effects have been with time-resolved spectroscopy, photo- created on the surface of polymers, studied for oil droplets fixed in gelatin chemical reaction, and laser fabrication, metals, and semiconductors. Further
metals, and semiconductors. Further- films as well as for photoresponsivewhich is now constructed as a laser more, arrays of reaction sites with dif- ness of microgels. A change in the manipulation-spectroscopy-reaction ferent functions are fabricated as a excited-state dimer formation efficiency system. The results will open a new way prototype of an integrated chemical of a dye suggests that the droplet becomes to control chemical reactions arbitrarily system.
viscous and/or the effective concentrain three-dimensional space.
With a scanning electrochemical tion of the solute becomes lower as the We previously reported a variable microscope (SECM), we have achieved diameter of the droplet is reduced. The angle, time-resolved, total-internal- in situ observation and fabrication of a rate of photoinduced volume expanreflection fluorescence spectroscopy for
sion of the microgels is now examined in detail by simultaneous measurements index droplet in solution, which cannot is required. In this work, we first of volume and absorption spectral be achieved by the conventional manip- developed an area-selective chemical changes (Ref 14). This makes it possi- ulation technique, were successfully vapor deposition (CVD) method and ble to interpret the unique behavior of accomplished using an “optical cag. then demonstrated that it could prothe photoinduced volume expansion ing" method with our laser system. duce micrometer size patterns of copreaction of the gels in terms of the Furthermore, simultaneous trapping per phthalocyanine derivatives from diffusion theory of gels.
of multiple particles was made possible 1,2,4,5-tetracyanobenzene (TCNB) We have succeeded in controlling a by scanning laser beams, producing (Ref 23,24). photochromic reaction by albumins. micrometer-size spatial patterns as well Copper films were patterned on The thermal back reaction of mero- as driving particles along the locus of silicon wafers by photolithography and cyanine to spiropyran was analyzed by the laser beams (Ref 20,21). This sys- wet etching techniques. The siliconassuming an enzymatic-like reaction tem was extended and combined with a copper substrate was sealed in a glass between the molecule and albumins, pulsed Nd3+:YAG laser that induces tube with TCNB and heated at differand the reaction rate was confirmed to photochemical reactions. The system ent temperatures. Over a narrow tembe accelerated by two orders of magni- is called a laser manipulation- perature range, selective CVD was tude in the presence of albumins. This spectroscopy-reaction system (Ref 22). achieved to produce copper phthalosuggests a new way of photochemical As an example, photopolymerization cyanine thin films on the copper patcontrol of reactions in a micrometer was employed for adhesion of polymer terns. By thermal annealing the films field.
particles, by which integrated struc- were converted to a polymer of the Chemical applications of the laser tures of polymer particles were assem- copper phthalocyanines, and their manipulation-spectroscopy-reaction bled with two trapping laser beams. chemical/physical properties were system are very fruitful.
We have succeeded, for the first greatly improved. Indeed, the conduc
time, in simultaneous optical trapping tivity of the copper phthalocyanine films Dynamic Functions of a and losing of a dye-doped polymer proved to be higher than that prior to Lasing Microsphere
particle suspended in water. Laser thermal annealing (Ref 25).
oscillation was confirmed by the appear- In order to apply the technique to Keiji Sasaki, Dynamic Spectroscopy ance of sharp resonance peaks in the fabricate microchemical functional sites, Group
emission spectrum. Photon tunneling an area-selective CVD of copper
from a lasing microspherical cavity to phthalocyanines was also performed The interaction between laser light the other particle was also demonstrated on insulating and optically transparent and a microsphere such as a liquid by using the two-beam trapping tech- materials (Ref 26). droplet, a polymer latex particle, or a nique. Optically manipulated lasing Since copper phthalocyanine and microcapsule leads to two interesting microspheres are promising in surface its polymers are expected to be photophenomena. One concerns optical trap- profiling, and microspectroscopic active materials, sensing materials, and ping of a microsphere induced by opti- measurements, and act as a novel light catalysts, the present technique has cal momentum changes. The other is source for photochemical reactions in enormous promise. Further applicaoptical resonance within a microsphere, small geometries.
tions of the selective CVD method to in which light propagates in a circum
other organic compounds and fabricaferential manner to create a standing Micrometer Selective Deposi- tion of materials surfaces should evenwave field similar to that in a lasertion of Polymers
tually allow one to prepare microphocavity. We have applied these phenom
toconversion systems. ena to realize spatial, dynamical, and Atsushi Sekiguchi, Microchemical Funcchemical manipulation of individual tion Group
SAKAKI QUANTUM WAVE microspheres and for fabricating minute
PROJECT: MANIPULATION reaction fields (Ref 15,16).
Organic thin films have received OF ELECTRON WAVES We developed a laser scanning much attention because of their new IN A QUANTUM micromanipulation system, in which chemical/physical properties and func- MICROSTRUCTURE two trapping laser beams were inde- tions that are not expected for inorpendently scanned by computer- ganic materials. In order to prepare Project Director: Hiroyuki Sakaki controlled galvano mirrors (Ref 17- functional chemical reaction sites based 19). Laser trapping and manipulation on organic compounds, fabrication of The aims of this project are threeof a metal particle or a low refractive films with micrometer spatial resolution fold: (1) exploration of the design methodology and the fabrication tech- (QW) and quantum boxes (QB). Atomic
(QW) and quantum boxes (QB). Atomic fabrication of quantum microstructures. nology of materials at an atomic scale layer epitaxy (ALE) is one of the A newly designed ultra-high vacuum to control electron waves within a promising technologies to realize these system has been established in order to solid, (2) analyses and predictive structures because of the digital nature fabricate inversion-type quantum wires syntheses of new quantum phenomena of monolayer/cycle growth. This char- (QWIS) by etching the sample of quanin semiconductor microstructures acteristic is due to the chemical inter- tum wells into V-shaped grooves and having future sizes comparable with action saturation between a substrate by subsequent regrowth on the etched electron wavelength (100 Å), and surface and a reactant source gas. In sidewalls (Ref 30). The formation of (3) clarification of the advantages and this report, the growth study of micro- the V-grooves has been achieved by in limits of electronic and optical devices structures by chloride ALE is presented situ microlithography of GaAs using using such new phenomena and/or new (Ref 27). First, the growth kinetics study electron beam assisted gas etching. A materials.
of chloride ALE using in situ optical second method to make QWLs by MBE, For these purposes, we are studying reflection measurements during ALE growth on a reverse-mesa shaped GaAs (1) material and process technologies growth is described. Clear reflection substrate, is now in progress (Ref 31). atan atomicscale to fabricate quantum intensity saturation was observed, cor- This method takes advantage of the microstructures, (2) the physics of elec- responding to self-limiting growth. The appearance of (111)B facets on the grown tron wave phenomena in quantum nature of the surface that causes the layer, which is due to the fact that the microstructures and their application self-limiting growth was also discussed. mobility of Ga atoms on the surface to devices, and (3) the formation of Second, T-shaped QW structures were greatly depends on the crystallographic quantum hybrid materials using novel grown by sidewall epitaxy of ALE. Two orientations. A 1-micron-wide components such as organic materials kinds of structures were tried. One was modulation-doped structure formed to expand the controllability of quan- fabricated by the overgrowth of GaAs/ on the (111)B facet has proven to be tum waves.
InGap by ALE on the cleaved edge of good enough to have a twoWe have successfully set up and now quantum wells. The other was formed dimensional electron gas by observing fully exploit the fabrication and char- by sidewall epitaxy on the (111)B planes, the Shubnikov-de Haas oscillation in acterization facilities for quantum which appeared by in situ selective gas magnetoresistance. microstructures. Though most of the arching of quantum wells. Conditions
In order to characterize quantum fabrication efforts are devoted to clarify- for obtaining mirror-like and smooth microstructures, a measurement sysing various elementary processes such surfaces by gas etching for InGaP/GaAs tem using ultra-short-pulse lasers, a as microscopic processes of growth, heterostructures are also presented. superconducting magnet, and an FTIR deposition, and etching at present, we Finally, band discontinuity between spectrometer has been installed. will combine them in order to build InGaP and GaAs was evaluated by In the field of theoretical analysis, quantum microstructures in the near
photoluminescence (PL) and PL exci- we estimated some properties of QWIS future and will make an effort to inves- tation spectroscopy of InGaP/GaAs and designed several novel quantum tigate their properties. In the field of quantum wells grown by ALE devices (Ref 32-35). theoretical studies, we have been and (Ref 28,29). The discontinuity of conwill be continually pursuing to propose duction bands was found to be approx- Electronic and Optical novel ideas based on quantum waves imately 0.06 eV. This result will be Properties of Organic and to deepen these understandings. used to design the T-shaped quantum Quantum Structures
wire structures. Fabrication of Microstructures
Hitoshi Akimichi, Quantum Hybrid by Atomic-Layer-Controlled Making Quantum Wire
Structures by Molecular
Novel quantum structure devices Akira Usui, Quantum Hyperstructure
using organic materials are expected to Group (Electrotechnical Laboratory, A. Shimizu, Exploratory Device and
A. Shimizu, Exploratory Device and show interesting properties. Conjugated Tsukuba) Physics Group
pi-electron materials such as oligo
thiophenes and oligoacenes can be It is desired to develop growth tech- Molecular beam epitaxy (MBE), in excellent candidates for these devices. nologies with a self-limiting growth which crystal growth occurs in ultra- To investigate the structural, electronic, mechanism for the fabrication of high vacuum conditions, is one of the and optical properties of these matemicrostructures such as quantum wires most promising techniques for rials, we fabricated pure and well-ordered thin films of the materials using an equally important for the expression Three-Dimensional ultra-high vacuum evaporation and regulation of the genomic infor- Reconstruction of chamber.
mation are the geometry of the genome Chromosomes in a Cell In this report, we show the field and the positional orientation of the effect transistor (FET) characteristics chromosomes within the cell. From this Yoshitaro Nakano and Kouichi Kojima, of the alkyloligothiophenes (degree of perspective we prefer not to sequence Research Group of Chromosome polymerization: 3-6), oligoacenes, and all of the human genome. Instead, we Dynamics other pi-electron materials (Ref 36). are taking the view that the many DNA As a result, we have found that the sequences without any known biologi- Little is known about the structure materials with smaller ionization poten- cal functions at the moment may have of nuclei, but it is thought that chromotial have larger mobility. Structural significance in the geometry of the somes occupy a discrete territory in the control of oligoacene (pentacene, tetra- genome.
interphase nucleus and specific cene) thin films under various evapo- Our current studies are to identify chromatin arrangements reflect proration conditions is currently under the genes, chromosome domains, and cesses of cellular differentiation and investigation by optical absorption DNA sequences that are responsible cell specific gene expression. To invesspectroscopy and x-ray diffraction for the mental faculties and genomic tigate the three-dimensional organiza(Ref 37,38). The results for layered struc- behavior related to chromosome pair- tion of chromosomes in nuclei and its ture with two different species of oligo- ing. To this end, specific regions of possible functional significance, we acenes are also reported.
human chromosomes are being laser are constructing equipment with which
microdissected and then segmented we can visualize intranuclear threeIKEDA GENOSPHERE
according to chromosome maps and dimensional chromosome topography. PROJECT: HOW DO WE the generated regional chromosome Though any optical microscopic ACCESS HUMAN GENOME DNA clones are studied. New instru- image of the specimen is contaminated ORGANIZATION?
ments are also being developed that with out-of-focus information, the digital
will allow such a real-time monitoring image processing method can remove Project Director: Joh-E Ikeda
of human chromosomes within a cellas its contribution. At first we obtained
to their relative positions and orienta- characteristic three-dimensional freAll of the characteristics of every tions within a nucleus. These new devices quency response of the optical system organism depend on genetic informa- will result in a real-time, three- by direct experimental measurement tion. It is the DNA molecule, the genetic dimensional human genome atlas. using fluorescent microbeads. Then we instructions inscribed in every cell, that
used the frequency response to obtain tells a body how to grow, survive, and Molecular Studies of the the true image by the Fourier transreproduce. The DNA molecule, a Functional Domains of the form of the observed image. densely packed configuration with Human Genome nuclear proteins in the cell, is con
AONO ATOMCRAFT structed of an unbroken string of bil- Haruhiko Yokoi, Research Group of Gene
Haruhiko Yokoi, Research Group of Gene PROJECT: OPENING OF lions of nucleotides. These genetic Function
"ATOMCRAFT” sequences are commands for protein subunits, enzymes, and hormones; New methodologies need to be Project Director: Masakazu Aono commands for turning genes on and developed to study the genomes of higher off; the recipe for how the configura- organisms such as humans because they “Atomcraft,” which is our newly tion of the chromosomes can change have far larger quantities of informa- coined word, expresses a new world of during the cell cycle; and the recipe for tion and more complex functions than possibilities where we may manipulate how the cells can divide and differenti- those of bacteria. We have established
an atom or a group of atoms at will to ate. All genetic material harbored in a methods to dissect specific domains of create artificial micromaterials with cell's nucleus is called the genome. The chromosomes and analyze the infor- novel atomic arrangement and elecgenome also governs behavior related mation or functional units within them. tronic properties, nanometer microto various activities, including neural. By these means, it will be possible to patterns exhibiting a novel electronic
For many years it has been gener- investigate the higher phenomena of or opiical function and for huge memally considered that the genome is a life such as mental activity in humans. ories, etc. Although this was only a biolinguistics composed of four nucleo
dream a decade ago, the dream has tides. We are exploring the idea that