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Francesco Lemmi

Bio: Francesco Lemmi is an academic researcher from DuPont. The author has contributed to research in topics: Common emitter & Silicon. The author has an hindex of 13, co-authored 27 publications receiving 528 citations.
Topics: Common emitter, Silicon, Wafer, Thin film, Solar cell

Papers
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Patent
04 Dec 2007
TL;DR: In this paper, a method of forming a densified nanoparticle thin film is disclosed, which includes positioning a substrate in a first chamber; and depositing a nanoparticle ink, the nanoparticles ink including a set of Group IV semiconductor particles and a solvent.
Abstract: A method of forming a densified nanoparticle thin film is disclosed. The method includes positioning a substrate in a first chamber; and depositing a nanoparticle ink, the nanoparticle ink including a set of Group IV semiconductor particles and a solvent. The method also includes heating the nanoparticle ink to a first temperature between about 30°C and about 300°C, and for a first time period between about 1 minute and about 60 minutes, wherein the solvent is substantially removed, and a porous compact is formed; and positioning the substrate in a second chamber, the second chamber having a pressure of between about 1 x 10-7 Torr and about 1 x 10-4 Torr. The method further includes depositing on the porous compact a dielectric material; wherein the densified nanoparticle thin film is formed.

149 citations

Patent
02 Apr 2008
Abstract: A method for forming a contact to a substrate is disclosed. The method includes providing a substrate, the substrate being doped with a first dopant; and diffusing a second dopant into at least a first side of the substrate to form a second dopant region, the first side further including a first side surface area. The method also includes forming a dielectric layer on the first side of the substrate. The method further includes forming a set of composite layer regions on the dielectric layer, wherein each composite layer region of the set of composite layer regions further includes a set of Group IV semiconductor nanoparticles and a set of metal particles. The method also includes heating the set of composite layer regions to a first temperature, wherein at least some composite layer regions of the set of composite layer regions etch through the dielectric layer and form a set of contacts with the second dopant region.

51 citations

Patent
20 Mar 2008
TL;DR: In this paper, a device for generating electricity from solar radiation is disclosed, which includes a wafer doped with a first dopant, the wafer including a front side and a back side, wherein the front-side is configured to be exposed to the solar radiation.
Abstract: A device for generating electricity from solar radiation is disclosed. The device includes a wafer doped with a first dopant, the wafer including a front-side and a back-side, wherein the front-side is configured to be exposed to the solar radiation. The device also includes a fused Group IV nanoparticle thin film deposited on the front-side, wherein the nanoparticle thin film includes a second dopant, wherein the second dopant is a counter dopant. The device further includes a first electrode deposited on the nanoparticle thin film, and a second electrode deposited on the back-side, wherein when solar radiation is applied to the front-side, an electrical current is produced.

50 citations

Patent
04 Dec 2007
TL;DR: In this paper, a method of forming a densified nanoparticle thin film in a chamber is disclosed, which includes positioning a substrate in the chamber; and depositing a nanoparticle ink, the nanoparticles ink including a set of Group IV semiconductor particles and a solvent.
Abstract: A method of forming a densified nanoparticle thin film in a chamber is disclosed. The method includes positioning a substrate in the chamber; and depositing a nanoparticle ink, the nanoparticle ink including a set of Group IV semiconductor particles and a solvent. The method also includes heating the nanoparticle ink to a first temperature between about 30°C and about 300°C, and for a first time period between about 1 minute and about 60 minutes, wherein the solvent is substantially removed, and a porous compact is formed. The method further includes exposing the porous compact to an HF vapor for a second time period of between about 2 minutes and about 20 minutes, and heating the porous compact for a second temperature of between about 25°C and about 60° C; and heating the porous compact to a third temperature between about 100° C and about 1000° C, and for a third time period of between about 5 minutes and about 10 hours; wherein the densified nanoparticle thin film is formed.

50 citations

Patent
25 Sep 2007
TL;DR: In this paper, a device for generating electricity from solar radiation is disclosed, which includes a substrate, an insulating layer formed above the substrate, and a first electrode formed above an insulator layer.
Abstract: A device for generating electricity from solar radiation is disclosed. The device includes a substrate; an insulating layer formed above the substrate; and a first electrode formed above the insulating layer. The device also includes a first doped Group IV nanoparticle thin film deposited on the first electrode; and a second doped Group IV nanoparticle thin film deposited on the first doped Group IV nanoparticle thin film. The device further includes a third doped Group IV nanoparticle thin film deposited on the second doped Group IV nanoparticle thin film; a fourth doped Group IV nanoparticle thin film deposited on the third doped Group IV nanoparticle thin film; and, a second electrode formed on the fourth doped Group IV nanoparticle thin film. Wherein, when solar radiation is applied to the fourth doped Group IV nanoparticle thin film, an electrical current is produced.

29 citations


Cited by
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Patent
01 Aug 2008
TL;DR: In this article, the oxide semiconductor film has at least a crystallized region in a channel region, which is defined as a region of interest (ROI) for a semiconductor device.
Abstract: An object is to provide a semiconductor device of which a manufacturing process is not complicated and by which cost can be suppressed, by forming a thin film transistor using an oxide semiconductor film typified by zinc oxide, and a manufacturing method thereof. For the semiconductor device, a gate electrode is formed over a substrate; a gate insulating film is formed covering the gate electrode; an oxide semiconductor film is formed over the gate insulating film; and a first conductive film and a second conductive film are formed over the oxide semiconductor film. The oxide semiconductor film has at least a crystallized region in a channel region.

1,501 citations

Journal ArticleDOI
TL;DR: In this article, the efficiency of n-type silicon solar cells with a front side boron-doped emitter and a full-area tunnel oxide passivating electron contact was studied experimentally as a function of wafer thickness W and resistivity ρ b.

470 citations

Journal ArticleDOI
TL;DR: The fundamentals of nanocrystal formation in plasmas are discussed, practical implementations of plasma reactors are reviewed, the materials that have been produced with nonthermal plAsmas and surface chemistries that have be developed are surveyed, and an overview of applications of plasma-synthesized nanocrystals is provided.
Abstract: Nonthermal plasmas have emerged as a viable synthesis technique for nanocrystal materials. Inherently solvent and ligand-free, nonthermal plasmas offer the ability to synthesize high purity nanocrystals of materials that require high synthesis temperatures. The nonequilibrium environment in nonthermal plasmas has a number of attractive attributes: energetic surface reactions selectively heat the nanoparticles to temperatures that can strongly exceed the gas temperature; charging of nanoparticles through plasma electrons reduces or eliminates nanoparticle agglomeration; and the large difference between the chemical potentials of the gaseous growth species and the species bound to the nanoparticle surfaces facilitates nanocrystal doping. This paper reviews the state of the art in nonthermal plasma synthesis of nanocrystals. It discusses the fundamentals of nanocrystal formation in plasmas, reviews practical implementations of plasma reactors, surveys the materials that have been produced with nonthermal pla...

292 citations

Patent
28 Oct 2011
TL;DR: In this paper, a gas channel plate for a semiconductor process module is described, which includes a heat exchange surface including a plurality of heat exchange structures separated from one another by intervening gaps.
Abstract: Embodiments related to managing the process feed conditions for a semiconductor process module are provided. In one example, a gas channel plate for a semiconductor process module is provided. The example gas channel plate includes a heat exchange surface including a plurality of heat exchange structures separated from one another by intervening gaps. The example gas channel plate also includes a heat exchange fluid director plate support surface for supporting a heat exchange fluid director plate above the plurality of heat exchange structures so that at least a portion of the plurality of heat exchange structures are spaced from the heat exchange fluid director plate.

281 citations

Journal ArticleDOI
TL;DR: In this article, the important fundamental mechanisms of nanocrystal formation in plasmas, reviews the range of synthesis approaches reported in the literature and discusses some of the potential applications of plasma-synthesized semiconductor nanocrystals.
Abstract: Semiconductor nanocrystals have attracted considerable interest for a wide range of applications including light-emitting devices and displays, photovoltaic cells, nanoelectronic circuit elements, thermoelectric energy generation and luminescent markers in biomedicine A particular advantage of semiconductor nanocrystals compared with bulk materials rests in their size-tunable optical, mechanical and thermal properties While nanocrystals of ionically bonded semiconductors can conveniently be synthesized with liquid phase chemistry, covalently bonded semiconductors require higher synthesis temperatures Over the past decade, nonthermal plasmas have emerged as capable synthetic approaches for the covalently bonded semiconductor nanocrystals Among the main advantages of nanocrystal synthesis in plasmas is the unipolar electrical charging of nanocrystals that helps avoid or reduce particle agglomeration and the selective heating of nanoparticles immersed in low-pressure plasmas This paper discusses the important fundamental mechanisms of nanocrystal formation in plasmas, reviews the range of synthesis approaches reported in the literature and discusses some of the potential applications of plasma-synthesized semiconductor nanocrystals

259 citations