skip to main content

Explore Research Products in the NSF-PAR

Title: Investigation of Nano‐Gaps in Fractured β‐Ga 2 O 3 Nanomembranes Formed by Uniaxial Strain
Abstract

A free‐standing β‐Ga2O3, also called β‐Ga2O3nanomembrane (NM), is an important next‐generation wide bandgap semiconductor that can be used for myriad high‐performance future flexible electronics. However, details of structure‐property relationships of β‐Ga2O3NM under strain conditions have not yet investigated. In this paper, the electrical properties of β‐Ga2O3NM under different uniaxial strain conditions using various surface analysis methods are systematically investigated and layer‐delamination and fractures are revealed. The electrical characterization shows that the presence of nanometer‐sized gaps between fractured pieces in β‐Ga2O3NM causes a severe property degradation due to higher resistance and uneven charge distribution in β‐Ga2O3NM which is also confirmed by the multiphysics simulation. Interestingly, the degraded performance in β‐Ga2O3NM is substantially recovered by introducing excessive OH‐bonds in fractured β‐Ga2O3NM via the water vapor treatment. The X‐ray photoelectron spectroscopy study reveals that a formation of OH‐bonds by the water vapor treatment chemically connects nano‐gaps. Thus, the treated β‐Ga2O3samples exhibit reliable and stable recovered electrical properties up to ≈90% of their initial values. Therefore, this result offers a viable route for utilizing β‐Ga2O3NMs as a next‐generation material for a myriad of high‐performance flexible electronics and optoelectronic applications.

  more » « less
Award ID(s):
1809077
NSF-PAR ID:
10453180
Author(s) / Creator(s):
 ;  ;  ;  ;  ;  ;  
Publisher / Repository:
Wiley Blackwell (John Wiley & Sons)
Date Published:
Journal Name:
Advanced Electronic Materials
Volume:
7
Issue:
2
ISSN:
2199-160X
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. ; ; ; ; ; ; ; ( , Journal of Materials Chemistry C)
    null (Ed.)
    This paper reports the fabrication of β-Ga 2 O 3 nanomembrane (NM) based flexible photodetectors (PDs) and the investigation of their optoelectrical properties under bending conditions. Flexible β-Ga 2 O 3 NM PDs exhibited reliable solar-blind photo-detection under bending conditions. Interestingly, a slight shifting in wavelength of the maximum solar-blind photo-current was observed under the bending condition. To investigate the reason for this peak shifting, the optical properties of β-Ga 2 O 3 NMs under different strain conditions were measured, which revealed changes in the refractive index, extinction coefficient and bandgap of strained β-Ga 2 O 3 NMs due to the presence of nano-sized cracks in the β-Ga 2 O 3 NMs. The results of a multiphysics simulation and a density-functional theory calculation for strained β-Ga 2 O 3 NMs showed that the conduction band minimum and the valence band maximum states were shifted nearly linearly with the applied uniaxial strain, which caused changes in the optical properties of the β-Ga 2 O 3 NM. We also found that nano-gaps in the β-Ga 2 O 3 NM play a crucial role in enhancing the photoresponsivity of the β-Ga 2 O 3 NM PD under bending conditions due to the secondary light absorption caused by reflected light from the nano-gap surfaces. Therefore, this research provides a viable route to realize high-performance flexible photodetectors, which are one of the indispensable components in future flexible sensor systems. 
    more » « less
  2. ; ; ( , ECS Journal of Solid State Science and Technology)

    Theβ-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
  3. ; ( , Journal of Physics D: Applied Physics)
    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
  4. ; ; ( , Advanced Materials Technologies)
    Abstract

    In this study, Si/β‐Ga2O3solar‐blind photodetectors (PDs) have been demonstrated via micro‐transfer printing of a single crystalline Si pillar on β‐Ga2O3. Unlike other previous approaches for β‐Ga2O3based heterojunction, this new single crystalline p‐n Si/β‐Ga2O3heterojunction has a particle‐free heterointerface and does not show any sign of internal strain after the heterogeneous integration that is confirmed by Raman spectroscopy. As a result, PDs exhibit extremely high photoresponsivity (748 A W−1), quantum efficiency (3.67 × 105%), and UV/visible rejection ratio (≈105) under UV light illumination. This result is believed to provide a viable route for the realization of high‐performance solar‐blind photodetection systems, which form some of the most indispensable and important components in high‐performance next‐generation security, biomedical, and environmental monitoring systems. Also, the unique heterogeneous integration method allows us to realize a variety of β‐Ga2O3based heterostructures that can further enhance the optical performances of β‐Ga2O3based PDs.

     
    more » « less
  5. ; ; ; ; ; ; ( , physica status solidi (a))
     
    more » « less
  • Citation Formats
  • MLA
  • APA
  • Chicago
  • BibTeX
  • Save / Share this Record
  • Send to Email