Methods of making a semiconductor layer from nanocrystals are disclosed. A film of nanocrystals capped with a ligand can be deposited onto a substrate; and the nanocrystals can be irradiated with one or more pulses of light. The pulsed light can be used to substantially remove the ligands from the nanocrystals and leave the nanocrystals unsintered or sintered, thereby providing a semiconductor layer. Layered structures comprising these semiconductor layers with an electrode are also disclosed. Devices comprising such layered structures are also disclosed.

A system for manufacture of I-III-VI-absorber photovoltaic cells involves sequential deposition of films comprising one or more of silver and copper, with one or more of aluminum indium and gallium, and one or more of sulfur, selenium, and tellurium, as compounds in multiple thin sublayers to form a composite absorber layer. In an embodiment, the method is adapted to roll-to-roll processing of photovoltaic cells. In an embodiment, the method is adapted to preparation of a CIGS absorber layer having graded composition through the layer of substitutions such as tellurium near the base contact and silver near the heterojunction partner layer, or through gradations in indium and gallium content. In a particular embodiment, the graded composition is enriched in gallium at a base of the layer, and silver at the top of the layer. In an embodiment, each sublayer is deposited by co-evaporation of copper, indium, gallium, and selenium, which react in-situ to form CIGS. In a particular embodiment, a special selenium or tellurium source, valve and delivery subsystem is made of quartz, graphite, coated graphite, or molybdenum. In a particular embodiment, an ion-beam source module configured for surface smoothing the solar absorber sublayer surface before passing through the final deposition zone.

A stack for a semiconductor device and a method for making the stack are disclosed. The stack includes a plurality of sacrificial layers in which each sacrificial layer has a first lattice parameter; and at least one channel layer that has a second lattice parameter in which the first lattice parameter is less than or equal to the second lattice parameter, and each channel layer is disposed between and in contact with two sacrificial layers and includes a compressive strain or a neutral strain based on a difference between the first lattice parameter and the second lattice parameter.

A transistor structure includes a first channel layer over a second channel layer, where the first and the second channel layers include a monocrystalline transition metal dichalcogenide (TMD). The transistor structure further includes a source material coupled to a first end of the first and second channel layers, a drain material coupled to a second end of the first and second channel layers, a gate electrode between the source material and the drain material, and between the first channel layer and the second channel layer and a gate dielectric between the gate electrode and each of the first channel layer and the second channel layer.

A method of fabricating a semiconductor device having two dimensional (2D) lateral hetero-structures includes forming alternating regions of a first metal dichalcogenide film and a second metal dichalcogenide film extending along a surface of a first substrate. The first metal dichalcogenide and the second metal dichalcogenide films are different metal dichalcogenides. Each second metal dichalcogenide film region is bordered on opposing lateral sides by a region of the first metal dichalcogenide film, as seen in cross-sectional view.

Provided are van der Waals (VDW) films comprising one or more transition metal chalcogenide (TMD) films. Also provided are methods of making VDW films. The methods are based on transfer of monolayer TMD films under vacuum, for example, using a handle layer. Also provided are apparatuses and devices comprising one or more VDW film.

In an embodiment, a method includes providing a substrate and epitaxially growing a semiconductor layer of a semiconductor material on the substrate using physical vapor deposition, wherein the semiconductor material has a tetragonal phase, wherein the semiconductor material has the general formula: (In.sub.1-xM.sub.x)(Te.sub.1-yZ.sub.y), and wherein M=Ga, Zn, Cd, Hg, Tl, Sn, Pb, Ge, or combinations thereof, Z═As, S, Se, Sb, or combinations thereof, x=0-0.1, and y=0-0.1, or wherein the semiconductor material has the general formula: (In.sub.1-xTl.sub.x)(Te.sub.1-ySe.sub.y) with x=0-1 and y=0-1.

A process for epitaxying GaSe on a [111]-oriented silicon substrate, includes a step of selecting a [111]-oriented silicon substrate resulting from cutting a silicon bar in a miscut direction which is one of the three [11-2] crystallographic directions, the miscut angle (α) being smaller than or equal to 0.1°, the obtained surface of the substrate forming a vicinal surface exhibiting a plurality of terraces and at least one step between two terraces; a passivation step consisting of depositing an atomic bilayer of gallium and of selenium on the vicinal surface of the silicon substrate so as to form a passivated vicinal surface made of silicon-gallium-selenium (Si—Ga—Se), said passivated vicinal surface exhibiting a plurality of passivated terraces and at least one passivated step between two passivated terraces; a step of forming a layer of two-dimensional GaSe by epitaxy on the passivated surface, said formation step comprising a step of nucleation from each passivated step and a step of lateral growth on the passivated terraces from the nuclei obtained in the nucleation step. A structure obtained by means of the epitaxying process is also provided.

Embodiments including apparatus, systems, and methods for nanofabrication are provided. In one example, a method of manufacturing a semiconductor device includes forming a two-dimensional (2D) layer comprising a 2D material on a first substrate and forming a plurality of holes in the 2D layer to create a patterned 2D layer. The method also includes forming a single-crystalline film on the patterned 2D layer and transferring the single-crystalline film onto a second substrate.

Provided are a black phosphorus-two dimensional material complex and a method of manufacturing the black phosphorus-two dimensional material complex. The black phosphorus-two dimensional material complex includes: first and second two-dimensional material layers, which each have a two-dimensional crystal structure and are coupled to each other by van der Waals force; and a black phosphorus sheet which between the first and second two-dimensional material layers and having a two-dimensional crystal structure in which a plurality of phosphorus atoms are covalently bonded.