Abstract: A method of growing fully relaxed SiGeSn buffer layers on Si substrates to produce virtual substrates for the epitaxial growth of high quality GeSn films suitable for high performance infrared (IR) optoelectronic device technology directly integrated on silicon. Growing the SiGeSn virtual substrate uses a precisely decreasing growth temperature and Si flux and a precisely increasing Ge and Sn flux. The virtual substrates may have a slightly larger lattice constant than that of the target GeSn alloy to impose a precise degree of tensile strain resulting in a direct band gap for the target GeSn alloy.

Abstract: A 3C—SiC buffer layer on Si(001) comprising a porous buffer layer of 3C—SiC on a Si(001) substrate, wherein the porous buffer layer is produced through a solid state reaction, and wherein an amorphous carbon layer on the Si(001) substrate is deposited by magnetron sputtering of a C target at room temperature at a rate of 0.8 nm/min.

Abstract: A hydrogen-free amorphous dielectric insulating film having a high material density and a low density of tunneling states. The film is prepared by deposition of a dielectric material on a substrate having a high substrate temperature Tsub under high vacuum and at a controlled low deposition rate. In one embodiment, the film is amorphous silicon while in another embodiment the film is amorphous germanium.

Abstract: A 3C—SiC buffer layer on Si(001) comprising a porous buffer layer of 3C—SiC on a Si(001) substrate, wherein the porous buffer layer is produced through a solid state reaction, and wherein an amorphous carbon layer on the Si(001) substrate is deposited by magnetron sputtering of a C target at room temperature at a rate of 0.8 nm/min.

Abstract: A method of making a SiC buffer layer on a Si substrate comprising depositing an amorphous carbon layer on a Si(001) substrate, controlling the thickness of the amorphous carbon layer by controlling the time of the step of depositing the amorphous carbon layer, and forming a deposited film. A 3C—SiC buffer layer on Si(001) comprising a porous buffer layer of 3C—SiC on a Si substrate wherein the porous buffer layer is produced through a solid state reaction.

Abstract: A hydrogen-free amorphous dielectric insulating film having a high material density and a low density of tunneling states. The film is prepared by deposition of a dielectric material on a substrate having a high substrate temperature Tsub under high vacuum and at a controlled low deposition rate. In one embodiment, the film is amorphous silicon while in another embodiment the film is amorphous germanium.

Abstract: A method of making a SiC buffer layer on a Si substrate comprising depositing an amorphous carbon layer on a Si(001) substrate, controlling the thickness of the amorphous carbon layer by controlling the time of the step of depositing the amorphous carbon layer, and forming a deposited film. A 3C-SiC buffer layer on Si(001) comprising a porous buffer layer of 3C-SiC on a Si substrate wherein the porous buffer layer is produced through a solid state reaction.

Abstract: A method of making a low-dimensional material chemical vapor sensor comprising exfoliating MoS2, applying the monolayer flakes of MoS2 onto a SiO2/Si wafer, applying a methylmethacrylate (MMA)/polymethylmethacrylate (PMMA) film, defining trenches for the deposition of metal contacts, and depositing one of Ti/Au, Au, and Pt in the trench and resulting in a MoS2 sensor. A low-dimensional material chemical vapor sensor comprising monolayer flakes of MoS2, trenches in the SiO2/Si wafer, metal contacts in the trenches, and thereby resulting in a MoS2 sensor. A full spectrum sensing suite comprising similarly fabricated parallel sensors made from a variety of low-dimensional materials including graphene, carbon nanotubes, MoS2, BN, and the family of transition metal dichalcogenides. The sensing suites are small, robust, sensitive, low-power, inexpensive, and fast in their response to chemical vapor analytes.

Abstract: Processes for preparation of an epitaxial graphene surface to make it suitable for deposition of high-? oxide-based dielectric compounds such as Al2O3, HfO2, TaO5, or TiO2 are provided. A first process combines ex situ wet chemistry conditioning of an epitaxially grown graphene sample with an in situ pulsing sequence in the ALD reactor. A second process combines ex situ dry chemistry conditioning of the epitaxially grown graphene sample with the in situ pulsing sequence.

Abstract: Processes for preparation of an epitaxial graphene surface to make it suitable for deposition of high-? oxide-based dielectric compounds such as Al2O3, HfO2, TaO5, or TiO2 are provided. A first process combines ex situ wet chemistry conditioning of an epitaxially grown graphene sample with an in situ pulsing sequence in the ALD reactor. A second process combines ex situ dry chemistry conditioning of the epitaxially grown graphene sample with the in situ pulsing sequence.

Abstract: Processes for preparation of an epitaxial graphene surface to make it suitable for deposition of high-? oxide-based dielectric compounds such as Al2O3, HfO2, TaO5, or TiO2 are provided. A first process combines ex situ wet chemistry conditioning of an epitaxially grown graphene sample with an in situ pulsing sequence in the ALD reactor. A second process combines ex situ dry chemistry conditioning of the epitaxially grown graphene sample with the in situ pulsing sequence.

Abstract: A method of making a low-dimensional material chemical vapor sensor comprising exfoliating MoS2, applying the monolayer flakes of MoS2 onto a SiO2/Si wafer, applying a methylmethacrylate (MMA)/polymethylmethacrylate (PMMA) film, defining trenches for the deposition of metal contacts, and depositing one of Ti/Au, Au, and Pt in the trench and resulting in a MoS2 sensor. A low-dimensional material chemical vapor sensor comprising monolayer flakes of MoS2, trenches in the SiO2/Si wafer, metal contacts in the trenches, and thereby resulting in a MoS2 sensor. A full spectrum sensing suite comprising similarly fabricated parallel sensors made from a variety of low-dimensional materials including graphene, carbon nanotubes, MoS2, BN, and the family of transition metal dichalcogenides. The sensing suites are small, robust, sensitive, low-power, inexpensive, and fast in their response to chemical vapor analytes.

Abstract: A method of preparing GaN material includes subjecting a GaN substrate to at least two cycles of Ga deposition and desorption, then applying a layer of AlN to the GaN substrate, then growing GaN on the AlN layer by molecular beam epitaxy. This results in reduced concentrations of oxygen, carbon, and silicon impurities.

Abstract: Processes for preparation of an epitaxial graphene surface to make it suitable for deposition of high-? oxide-based dielectric compounds such as Al2O3, HfO2, TaO5, or TiO2 are provided. A first process combines ex situ wet chemistry conditioning of an epitaxially grown graphene sample with an in situ pulsing sequence in the ALD reactor. A second process combines ex situ dry chemistry conditioning of the epitaxially grown graphene sample with the in situ pulsing sequence.

Abstract: Processes for preparation of an epitaxial graphene surface to make it suitable for deposition of high-? oxide-based dielectric compounds such as Al2O3, HfO2, TaO5, or TiO2 are provided. A first process combines ex situ wet chemistry conditioning of an epitaxially grown graphene sample with an in situ pulsing sequence in the ALD reactor. A second process combines ex situ dry chemistry conditioning of the epitaxially grown graphene sample with the in situ pulsing sequence.

Abstract: Processes for preparation of an epitaxial graphene surface to make it suitable for deposition of high-? oxide-based dielectric compounds such as Al2O3, HfO2, TaO5, or TiO2 are provided. A first process combines ex situ wet chemistry conditioning of an epitaxially grown graphene sample with an in situ pulsing sequence in the ALD reactor. A second process combines ex situ dry chemistry conditioning of the epitaxially grown graphene sample with the in situ pulsing sequence.