The
Nanothermometry is the study of temperature at the submicron scale with a broad range of potential applications, such as cellular studies or electronics. Molecular luminescent‐based nanothermometers offer a non‐contact means to record these temperatures with high spatial resolution and thermal sensitivity. A luminescent‐based molecular thermometer comprised of visible‐emitting Ga3+/Tb3+and Ga3+/Sm3+metallacrowns (MCs) achieved remarkable relative thermal sensitivity associated with very low temperature uncertainty of
- Award ID(s):
- 1664964
- NSF-PAR ID:
- 10256342
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Chemistry – A European Journal
- Volume:
- 26
- Issue:
- 61
- ISSN:
- 0947-6539
- Page Range / eLocation ID:
- p. 13792-13796
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
more » « less
β -Ga2O3nanomembrane (NM)/diamond heterostructure is one of the promising ultra-wide bandgap heterostructures that offers numerous complementary advantages from both materials. In this work, we have investigated the thermal properties of theβ -Ga2O3NM/diamond heterostructure with three different thicknesses ofβ -Ga2O3nanomembranes (NMs), namely 100 nm, 1000 nm, and 4000 nm thickβ -Ga2O3NMs using Raman thermometry. The thermal property—temperature relationships of theseβ -Ga2O3NM/diamond heterostructures, such as thermal conductivity and interfacial thermal boundary conductance were determined under different temperature conditions (from 100 K to 500 K with a 40 K interval). The result provides benchmark knowledge about the thermal conductivity ofβ -Ga2O3NMs over a wide temperature range for the design of novelβ -Ga2O3-based power electronics and optoelectronics. -
more » « less
The ion implantation of H+and D+into Ga2O3produces several O–H and O–D centers that have been investigated by vibrational spectroscopy. These defects include the dominant VGa(1)-2H and VGa(1)-2D centers studied previously along with additional defects that can be converted into this structure by thermal annealing. The polarization dependence of the spectra has also been analyzed to determine the directions of the transition moments of the defects and to provide information about defect structure. Our experimental results show that the implantation of H+(or D+) into Ga2O3produces two classes of defects with different polarization properties. Theory finds that these O–H (or O–D) centers are based on two shifted configurations of a Ga(1) vacancy that trap H (or D) atom(s). The interaction of VGa(1)-nD centers with other defects in the implanted samples has also been investigated to help explain the number of O–D lines seen and their reactions upon annealing. Hydrogenated divacancy VGa(1)-VOcenters have been considered as an example.
-
more » « less
Abstract Here, high power flexible Schottky barrier diodes (SBDs) are demonstrated on a plastic substrate using single crystalline β‐Ga2O3nanomembranes (NMs). In order to realize flexible high power β‐Ga2O3SBDs, sub‐micron thick freestanding β‐Ga2O3NMs are created from a bulk β‐Ga2O3substrate and transfer‐printed onto the plastic substrate via a microtransfer printing method. It is revealed that the material property of β‐Ga2O3NMs such as crystal structure, electron affinity, and bandgap remains unchanged compared with its bulk properties. Flexible β‐Ga2O3SBDs exhibit the record high critical breakdown field strength (
E c) of 1.2 MV cm−1in the flat condition and 1.07 MV cm−1ofE cunder the bending condition. Overall, flexible β‐Ga2O3SBDs offer great promise for future flexible energy convergence systems and are expected to provide a much larger and more versatile platform to address a broader range of high‐performance flexible applications. -
more » « less
Large area (1 mm2) vertical NiO/
β n-Ga2O/n+Ga2O3heterojunction rectifiers are demonstrated with simultaneous high breakdown voltage and large conducting currents. The devices showed breakdown voltages (VB) of 3.6 kV for a drift layer doping of 8 × 1015cm−3, with 4.8 A forward current. This performance is higher than the unipolar 1D limit for GaN, showing the promise ofβ -Ga2O3for future generations of high-power rectification devices. The breakdown voltage was a strong function of drift region carrier concentration, with VBdropping to 1.76 kV for epi layer doping of 2 × 1016cm−3. The power figure-of-merit, VB2/RON, was 8.64 GW·cm−2, where RONis the on-state resistance (1.5 mΩ cm2). The on-off ratio switching from 12 to 0 V was 2.8 × 1013, while it was 2 × 1012switching from 100 V. The turn-on voltage was 1.8 V. The reverse recovery time was 42 ns, with a reverse recovery current of 34 mA. -
Abstract In this paper, transient delayed rise and fall times for beta gallium oxide ( β -Ga 2 O 3 ) nanomembrane (NM) Schottky barrier diodes (SBDs) formed on four different substrates (diamond, Si, sapphire, and polyimide) were measured using a sub-micron second resolution time-resolved electrical measurement system under different temperature conditions. The devices exhibited noticeably less-delayed turn on/turn off transient time when β -Ga 2 O 3 NM SBDs were built on a high thermal conductive (high- k ) substrate. Furthermore, a relationship between the β -Ga 2 O 3 NM thicknesses under different temperature conditions and their transient characteristics were systematically investigated and verified it using a multiphysics simulator. Overall, our results revealed the impact of various substrates with different thermal properties and different β -Ga 2 O 3 NM thicknesses on the performance of β -Ga 2 O 3 NM-based devices. Thus, the high- k substrate integration strategy will help design future β -Ga 2 O 3 -based devices by maximizing heat dissipation from the β -Ga 2 O 3 layer.more » « less
