7 research outputs found
A hybrid pulsed laser deposition approach to grow thin films of chalcogenides
Vapor-pressure mismatched materials such as transition metal chalcogenides
have emerged as electronic, photonic, and quantum materials with scientific and
technological importance. However, epitaxial growth of vapor-pressure
mismatched materials are challenging due to differences in the reactivity,
sticking coefficient, and surface adatom mobility of the mismatched species
constituting the material, especially sulfur containing compounds. Here, we
report a novel approach to grow chalcogenides - hybrid pulsed laser deposition
- wherein an organosulfur precursor is used as a sulfur source in conjunction
with pulsed laser deposition to regulate the stoichiometry of the deposited
films. Epitaxial or textured thin films of sulfides with variety of structure
and chemistry such as alkaline metal chalcogenides, main group chalcogenides,
transition metal chalcogenides and chalcogenide perovskites are demonstrated,
and structural characterization reveal improvement in thin film crystallinity,
and surface and interface roughness compared to the state-of-the-art. The
growth method can be broadened to other vapor-pressure mismatched chalcogenides
such as selenides and tellurides. Our work opens up opportunities for broader
epitaxial growth of chalcogenides, especially sulfide-based thin film
technological applications.Comment: 27 page
Unconventional Charge-density-wave Order in a Dilute d-band Semiconductor
Electron-lattice coupling effects in low dimensional materials give rise to
charge density wave (CDW) order and phase transitions. These phenomena are
critical ingredients for superconductivity and predominantly occur in metallic
model systems such as doped cuprates, transition metal dichalcogenides, and
more recently, in Kagome lattice materials. However, CDW in semiconducting
systems, specifically at the limit of low carrier concentration region, is
uncommon. Here, we combine electrical transport, synchrotron X-ray diffraction
and optical spectroscopy to discover CDW order in a quasi-one-dimensional (1D),
dilute d-band semiconductor, BaTiS3, which suggests the existence of strong
electron-phonon coupling. The CDW state further undergoes an unusual transition
featuring a sharp increase in carrier mobility. Our work establishes BaTiS3 as
a unique platform to study the CDW physics in the dilute filling limit to
explore novel electronic phases
Epitaxial rare-earth doped complex oxide thin films for infrared applications
Rare earth dopants are one of the most extensively studied optical emission centers for a broad range of applications such as laser optoelectronics, sensing, lighting, and quantum information technologies due to their narrow optical linewidth and exceptional coherence properties. Epitaxial doped oxide thin films can serve as a promising and controlled host to investigate rare-earth dopants suitable for scalable quantum memories, on-chip lasers and amplifiers. Here, we report high-quality epitaxial thin films of Tm-doped CaZrO grown by pulsed laser deposition for infrared optoelectronic and quantum memory applications. We perform extensive structural and chemical characterization to probe the crystallinity of the films and the doping behavior. Low temperature photoluminescence measurements show sharp radiative transitions in the short-wave infrared range of 1.75 - 2 \mu m