While the discovery of two-dimensional (2D) magnets opens the door for fundamental physics and next-generation spintronics, it is technically challenging to achieve the room-temperature ferromagnetic (FM) order in a way compatible with potential device applications. Here, we report the growth and properties of single- and few-layer CrTe2, a van der Waals (vdW) material, on bilayer graphene by molecular beam epitaxy (MBE). Intrinsic ferromagnetism with a Curie temperature (TC) up to 300 K, an atomic magnetic moment of ~0.21 $${\mu }_{{\rm{B}}}$$ μ B /Cr and perpendicular magnetic anisotropy (PMA) constant (Ku) of 4.89 × 105 erg/cm3 at room temperature in these few-monolayer films have been unambiguously evidenced by superconducting quantum interference device and X-ray magnetic circular dichroism. This intrinsic ferromagnetism has also been identified by the splitting of majority and minority band dispersions with ~0.2 eV at Г point using angle-resolved photoemission spectroscopy. The FM order is preserved with the film thickness down to a monolayer (TC ~ 200 K), benefiting from the strong PMA and weak interlayer coupling. The successful MBE growth of 2D FM CrTe2 films with room-temperature ferromagnetism opens a new avenue for developing large-scale 2D magnet-based spintronics devices.

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ZnO films were synthesized on GaAs substrates at different growth conditions by pulse laser deposition. High-purity ͑99.999%͒ oxygen was used as the ambient gas. The pressure of the ambient oxygen gas for ZnO film growth was varied from 20 to 50 mTorr, and the growth temperature from 300 to 450°C. ZnO films showed very strong bound exciton peaks located between 3.37 and 3.35 eV. The full width at half maximum of the bound exciton peak is less than 5 meV. These results indicate ZnO films on GaAs substrates can be used for optical devices such as light-emitting diodes. The other significant properties of textured ZnO films on GaAs substrates are described.

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We present the results of in situ x-ray scattering experiments that investigate the growth of Pb nanocrystalline islands on Si͑111͒. It is conclusively shown that the Pb nanocrystals do not reside on top of a Pb wetting layer. The nucleating Pb nanocrystals transform the highly disordered Pb wetting layer beneath the islands into well-ordered fcc Pb. The surface then consists of fcc Pb islands directly on top of the Si surface with the disordered wetting layer occupying the region between the islands. As the Pb nanocrystals coalesce at higher coverage we observe increasing disorder that is consistent with misfit strain relaxation. The confinement of the electron wave function in small objects leads to new energy levels that affect the object's total energy. Conversely, confinement influences an object's size by selecting those sizes that minimize the total energy. As a consequence, such "quantum size effects" (QSE) 1 cause metals grown on semiconductors to have certain film thicknesses or island heights that are more stable than others. 2-5

Producing a usable semiconducting form of graphene has plagued the development of graphene electronics for nearly two decades. Now that new preparation methods have become available, graphene's intrinsic properties can be measured and the search for semiconducting graphene has begun to produce results. This is the case of the first graphene "buffer" layer grown on SiC(0001) presented in this work. We show, contrary to assumptions of the last 40 years, that the buffer graphene layer is not commensurate with SiC. The new modulated structure we've found resolves a long-standing contradiction where ab initio calculations expect a metallic buffer, while experimentally it is found to be a semiconductor. Model calculations using the new incommensurate structure show that the semiconducting π-band character of the buffer comes from partially hybridized graphene incommensurate boundaries surrounding unperturbed graphene islands.