Semiconductor nanowires represent an important class of nanostructure building block for photovoltaics as well as direct solar-to-fuel application because of their high surface area, tunable bandgap and efficient charge transport and collection. In this talk, I will highlight several recent examples in this lab using semiconductor nanowires and their heterostructures for the purpose of solar energy harvesting. In addition, we have also discovered that the thermoconductivity of the silicon nanowires can be significantly reduced due to phonon scattering, pointing to a very promising approach to design better thermoelectrical materials. It is important to note that the engines that generate most of the world's power typically operate at only 30–40 per cent efficiency, releasing roughly 15 terawatts of heat to the environment. If this “wasted heat” could be recycled, the impact globally would be enormous. Our silicon nanowire thermoelectric technology could have a significant impact in alternative energy generation.

Semiconductor nanowires for energy conversion.

and Perspectives Sophie Carenco,†,‡,§,∥,⊥ David Portehault,*,†,‡,§ Ced́ric Boissier̀e,†,‡,§ Nicolas Meźailles, and Cleḿent Sanchez*,†,‡,§ †Chimie de la Matier̀e Condenseé de Paris, UPMC Univ Paris 06, UMR 7574, Colleg̀e de France, 11 Place Marcelin Berthelot, 75231 Paris Cedex 05, France ‡Chimie de la Matier̀e Condenseé de Paris, CNRS, UMR 77574, Colleg̀e de France, 11 Place Marcellin Berthelot, 75231 Paris Cedex 05, France Chimie de la Matier̀e Condenseé de Paris, Colleg̀e de France, 11 Place Marcellin Berthelot, 75231 Paris Cedex 05, France Laboratory Heteroelements and Coordination, Chemistry Department, Ecole Polytechnique, CNRS-UMR 7653, Palaiseau, France

Nanoscaled metal borides and phosphides: recent developments and perspectives

There has been an enormous infusion of new ideas in the field of solar cells over the last 15 years; discourse on energy transfer has gotten much richer, and nanostructures and nanomaterials have revolutionized the possibilities for new technological developments. However, solar energy cannot become ubiquitous in the world's power markets unless it can become economically competitive with legacy generation methods such as fossil fuels. The new edition of Dr. Stephen Fonash's definitive text points the way toward greater efficiency and cheaper production by adding coverage of cutting-edge topics in plasmonics, multi-exiton generation processes, nanostructures and nanomaterials such as quantum dots. This book's new structure improves readability by shifting many detailed equations to appendices, and balances the first edition's semiconductor coverage with an emphasis on thin-films. Further, it now demonstrates physical principles with simulations in the well-known AMPS computer code developed by the author. This classic text is now updated with new advances in nanomaterials and thin films that point the way to cheaper, more efficient solar energy production and, many of the detailed equations from the first edition have been shifted to appendices in order to improve readability. It carries important theoretical points are now accompanied by concrete demonstrations via included simulations created with the well-known AMPS computer code.

太阳电池器件物理 = Solar cell device physics

Synthesis forms a vital aspect of the science of nanomaterials. In this context, chemical methods have proved to be more effective and versatile than physical methods and have therefore, been employed widely to synthesize a variety of nanomaterials, including zero-dimensional nanocrystals, one-dimensional nanowires and nanotubes as well as two-dimensional nanofilms and nanowalls. Chemical synthesis of inorganic nanomaterials has been pursued vigorously in the last few years and in this article we provide a perspective on the present status of the subject. The article includes a discussion of nanocrystals and nanowires of metals, oxides, chalcogenides and pnictides. In addition, inorganic nanotubes and nanowalls have been reviewed. Some aspects of core–shell particles, oriented attachment and the use of liquid–liquid interfaces are also presented.

https://www.bibalex.org/CSSP/papers/Attachments/Dalton_review.pdf

Synthesis of inorganic nanomaterials

A review of nanowire growth promoted by alloys and non-alloying elements with emphasis on Au-assisted III-V nanowires

A novel design is presented for a nanowire/polymer hybrid photodiode. n-InP nanowires are grown directly onto an indium tin oxide (ITO) electrode to increase carrier collection efficiency and to eliminate the need for an expensive substrate. Experiments show that an ohmic contact is achieved between the nanowires and the ITO electrode. The nanowires are then enveloped by a high hole mobility conjugated polymer, poly(3-hexylthiophene). Compared to the control polymer-only device, the inclusion of InP nanowires increases the forward bias current conduction by 6-7 orders of magnitude. A high rectification ratio of 155 is achieved in these photodiodes along with a low ideality factor of 1.31. The hybrid device produces a photoresponse with a fill factor of 0.44, thus showing promise as an alternative to current polymer solar cell designs.

InP nanowire/polymer hybrid photodiode.

Vertically-aligned InP nanowires are grown by metalorganic chemical vapor deposition (MOCVD) without the use of a deposited metal catalyst. A surface reconstruction induces indium droplets to form on the surface and thus act as nucleation sites for nanowire growth. Vertical growth from the InP(111)B substrate along with transmission electron microscopy (TEM) analysis indicate epitaxial growth from the substrate in the [111]B direction. A uniform cross section along the longitudinal axis can be achieved by optimizing the input V∕III ratio. Small variations in the diameter and length are seen under optimal growth conditions.

Vertically aligned, catalyst-free InP nanowires grown by metalorganic chemical vapor deposition

A novel fabrication procedure is developed that allows for the direct measurement of the linear electrooptic coefficient of semiconducting nanowires to determine their viability for use in electrooptic devices. Vertically aligned InP nanowires are transferred from their growth substrate to a glass substrate using a host polymer, while still retaining the alignment of the nanowires. The linear electrooptic coefficient of the InP nanowires exhibited a 1-2 orders of magnitude enhancement over bulk InP and ranged from 31 to 147 pm/V. The figure of merit, n3r, exhibited a factor of 20 enhancement over lithium niobate and ranged from 1010 to 4817 pm/V.

Linear electrooptic coefficient of InP nanowires.

A steerable high-power microwave beam array includes an optical sub-system comprising a laser and an optical time delay unit and a parallel set of RF time delay units. The optical system and/or the RF delay subsystem are utilized to precisely delay the pulses from the microwave antenna elements to provide steerable beam forming.

High-power microwave beam steerable array and related methods

Silicon-on-insulator (SOI) substrates were created from two methods of ion cutting: thermal exfoliation (TE) and mechanical exfoliation (ME). These SOI films are characterized to discern the differences in electrical and other properties induced by the ME and TE processes. p-metal-oxide-semiconductor field-effect transistor were fabricated on these SOI substrates as well as on bulk silicon and their I-V characteristics measured and compared to point out materials differences created by the two methods. X-ray diffraction measurements were also performed to supplement the exploration of the TE and ME material properties. Overall the FETs fabricated from the ME SOI outperformed those made from the TE SOI and had similar Ion∕Ioff ratios and off-state drain-source leakage currents to the FETs fabricated from bulk Si.

Strain and electrical characterization of metal-oxide-semiconductor field-effect transistor fabricated on mechanically and thermally transferred silicon on insulator films

Clint J. Novotny

Papers

InP nanowire/polymer hybrid photodiode.

Vertically aligned, catalyst-free InP nanowires grown by metalorganic chemical vapor deposition

Linear electrooptic coefficient of InP nanowires.

High-power microwave beam steerable array and related methods

Strain and electrical characterization of metal-oxide-semiconductor field-effect transistor fabricated on mechanically and thermally transferred silicon on insulator films