A high figure‐of‐merit UV‐C solar‐blind photodetector (PD) fabricated from thin‐film beta‐gallium oxide (β‐Ga2O3) grown on
This content will become publicly available on May 16, 2024
With the astonishing advancement of present technology and increasing energy consumption, there is an ever‐increasing demand for energy‐efficient multifunctional sensors or transducers based on low‐cost, eco‐friendly material systems. In this context, self‐assembled vertically aligned
- Award ID(s):
- 1827745
- NSF-PAR ID:
- 10413937
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Materials Technologies
- Volume:
- 8
- Issue:
- 15
- ISSN:
- 2365-709X
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
n ‐Si substrates by plasma‐assisted molecular beam epitaxy is demonstrated. Film growth sequences for nucleation of Ga2O3on (100)‐ and (111)‐oriented Si substrates are developed, and the influence of crucial growth parameters is systematically investigated, namely, substrate temperature, oxygen flow rate, and plasma power on the functional properties of the PDs. The PDs show an ultra‐high responsivity of 837 A W−1and a fast ON/OFF time below 4 ms at −5 V. In addition, they display strong rectifying properties and a sharp cutoff below 280 nm with the average responsivities between 10 and 80 A W−1, a detectivity on the order of 1010 Jones, and rise/fall times between 4 and 500 ms. High photoconductive gain is likely to be due to the mid‐bandgap donor/acceptor defect levels, including oxygen vacancies in the form of self‐trapped holes. It is demonstrated that these defect levels can be modified by controlling the growth conditions, thereby allowing for tailoring of the PD characteristics for specific applications. The methodology represents a cost‐effective solution over homoepitaxial approaches, with characteristics that meet or exceed those reported previously, offering new possibilities for on‐wafer integration with Si opto‐electronics. -
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.
-
Abstract We report on the tunable and enhanced dielectric properties of tungsten (W) incorporated gallium oxide (Ga2O3) polycrystalline electroceramics for energy and power electronic device applications. The W‐incorporated Ga2O3(Ga2−2xWxO3, 0.00 ≤ x ≤ 0.20; GWO) compounds were synthesized by the high‐temperature solid‐state chemical reaction method by varying the W‐content. The fundamental aspects of the dielectric properties in correlation with the crystal structure, phase, and microstructure of the GWO polycrystalline compounds has been investigated in detail. A detailed study performed ascertains the W‐induced changes in the dielectric constant, loss tangent (tan
δ ) and ac conductivity. It was found that the dielectric constant increases with addition of W in the system as a function of temperature (25°C‐500°C). Frequency dependence (102‐106 Hz) of the dielectric constant follows the modified Debye model with a relaxation time of ∼20 to 90 μs and a spreading factor of 0.39 to 0.65. The dielectric constant of GWO is temperature independent almost until ∼300°C, and then increases rapidly in the range of 300°C to 500°C. W‐induced enhancement in the dielectric constant of GWO is fully evident in the frequency and temperature dependent dielectric studies. The frequency and temperature dependent tanδ reveals the typical behavior of relaxation loses in GWO. Small polaron hopping mechanism is evident in the frequency dependent electrical transport properties of GWO. The remarkable effect of W‐incorporation on the dielectric and electrical transport properties of Ga2O3is explained by a two‐layer heterogeneous model consisting of thick grains separated by very thin grain boundaries along with the formation of a Ga2O3‐WO3composite was able to account for the observed temperature and frequency dependent electrical properties in GWO. The results demonstrate that the structure, electrical and dielectric properties can be tailored by tuning W‐content in the GWO compounds. -
Growths of monoclinic (Al
x Ga1−x )2O3thin films up to 99% Al contents are demonstrated via metalorganic chemical vapor deposition (MOCVD) using trimethylgallium (TMGa) as the Ga precursor. The utilization of TMGa, rather than triethylgallium, enables a significant improvement of the growth rates (>2.5 μm h−1) of β‐(Alx Ga1−x )2O3thin films on (010), (100), and (01) β‐Ga2O3substrates. By systematically tuning the precursor molar flow rates, growth of coherently strained phase pure β‐(Alx Ga1−x )2O3films is demonstrated by comprehensive material characterizations via high‐resolution X‐ray diffraction (XRD) and atomic‐resolution scanning transmission electron microscopy (STEM) imaging. Monoclinic (Alx Ga1−x )2O3films with Al contents up to 99, 29, and 16% are achieved on (100), (010), and (01) β‐Ga2O3substrates, respectively. Beyond 29% of Al incorporation, the (010) (Alx Ga1−x )2O3films exhibit β‐ to γ‐phase segregation. β‐(Alx Ga1−x )2O3films grown on (01) β‐Ga2O3show local segregation of Al along (100) plane. Record‐high Al incorporations up to 99% in monoclinic (Alx Ga1−x )2O3grown on (100) Ga2O3are confirmed from XRD, STEM, electron nanodiffraction, and X‐ray photoelectron spectroscopy measurements. These results indicate great promises of MOCVD development of β‐(Alx Ga1−x )2O3films and heterostructures with high Al content and growth rates using TMGa for next‐generation high‐power and high‐frequency electronic devices. -
The growth of monoclinic phase‐pure gallium oxide (β‐Ga2O3) layers by metal–organic chemical vapor deposition on c‐plane sapphire and aluminum nitride (AlN) templates using silicon‐oxygen bonding (SiO
x ) as a phase stabilizer is reported. The β‐Ga2O3layers are grown using triethylgallium, oxygen, and silane for gallium, oxygen, and silicon precursors, respectively, at 700 °C, with and without silane flow in the process. The samples grown on sapphire with SiOx phase stabilization show a notable change from samples without phase stabilization in the roughness and resistivity, from 16.2 to 4.2 nm and from 85.82 to 135.64 Ω cm, respectively. X‐ray diffraction reveals a pure‐monoclinic phase, and Raman spatial mapping exhibits higher tensile strain in the films in the presence of SiOx . The β‐Ga2O3layers grown on an AlN template, using the same processes as for sapphire, show an excellent epitaxial relationship between β‐Ga2O3and AlN and have a significant change in β‐Ga2O3surface morphology.