Origin of Red Emission in β‐Ga<sub>2</sub>O<sub>3</sub> Analyzed by Cathodoluminescence and Photoluminescence Spectroscopy

Naresh-Kumar, G.; MacIntyre, Hazel; Subashchandran, Shanthi; Edwards, P. R.; Martin, Robert; Krishnamurthy, Daivasigamani; Kuramata, Akito

doi:10.1002/pssb.202000465

Cited by 28 publications

(11 citation statements)

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“…Oxygen interstitials have also been proposed to be the cause for green emission 32 , as has recombination between donor levels, introduced by the incorporation of Sn atoms, and holes at the valence band in Ga2O3 31,33,34 . The origin of the red emission is quite ambiguous, and the literature provides four plausible explanations involving doping by transition metals [34][35][36][37] , rare earth metals 38 , nitrogen, or hydrogen 32,39 . The peak structure is clarified by CL data from a cross-section, as discussed in the next section.…”

Section: Resultsmentioning

confidence: 99%

Correlation between deep-level defects and functional properties of β-(SnxGa1-x)2O3 on Si photodetectors

Hatipoglu

Hunter

Mukhopadhyay

et al. 2021

Journal of Applied Physics

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Heterogeneous integration of β-(SnxGa1-x)2O3 (TGO) UV-C photodetectors on silicon substrates by molecular beam epitaxy is demonstrated. Multimodal electron microscopy and spectroscopy techniques reveal a direct correlation between structural, compositional and optical properties of the TGO and the functional properties of the photodetectors. Wavelength dispersive X-ray spectroscopy results accurately determine the Sn concentrations (x) in the region of 0.020, and room temperature cathodoluminescence (CL) hyperspectral imaging shows changes in CL emission intensity in the TGO compared with a Ga2O3 sample with no Sn. Alloying Ga2O3 with Sn is shown to quench the red emission and enhance the blue emission. The increase in blue emission corresponds to the rise in VGa-related deep acceptors responsible for the high gain observed in the TGO detectors. A Ga2O3 nucleation layer is shown to improve the TGO surface quality and give better device properties compared to TGO grown directly onto the Si substrate, including a higher specific detectivity on the order of 10 12 Jones. Introduction:The UV spectrum covers a wide range of wavelengths spanning 10-400 nm. The earth's atmosphere and ozone absorb UV-C (100-280 nm), removing radiation with wavelengths shorter than 280 nm from the solar spectrum that reaches its surface. Therefore, a detector designed to be sensitive to only these wavelengths is not affected by solar radiation and is said #

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Section: Resultsmentioning

confidence: 99%

Correlation between deep-level defects and functional properties of β-(SnxGa1-x)2O3 on Si photodetectors

Hatipoglu

Hunter

Mukhopadhyay

et al. 2021

Journal of Applied Physics

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“…Finally, the red/near IR luminescence is also attributed to impurities, attributed mainly to nitrogen doping, [ 23,25 ] or due to rare earth and transition metal impurities. [ 31 ] However, N 2 free growth in our MBE chamber indicates that it could be hydrogen atoms, which can provide an electron to form OH bond by passivating an acceptor such as V Ga and absorb IR at vibrational mode. [ 32 ] It may also be related to ionic V O at different sites of the lattice.…”

Section: Resultsmentioning

confidence: 99%

High Figure‐of‐Merit Gallium Oxide UV Photodetector on Silicon by Molecular Beam Epitaxy: A Path toward Monolithic Integration

Mukhopadhyay

Hatipoglu

Sakthivel

et al. 2021

Advanced Photonics Research

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A high figure‐of‐merit UV‐C solar‐blind photodetector (PD) fabricated from thin‐film beta‐gallium oxide (β‐Ga2O3) grown on n‐Si substrates by plasma‐assisted molecular beam epitaxy is demonstrated. Film growth sequences for nucleation of Ga2O3 on (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−1 and 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.

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“…The only difference is the emission energy because of the difference in the bandgap between the two phases. Therefore, it is likely that the origin of each emission peak from the κ-phase is identical to that from the β-phase. , The main ultraviolet emission at about 340 nm has been attributed to the recombination between the electrons and self-trapped holes or the recombination of self-trapped excitons. The emission at 470 nm comes from the donor–acceptor pairs (DAPs) in which the anion and cation vacancies are responsible for the electrons and holes, respectively.…”

Section: Results and Discussionmentioning

confidence: 99%

Sn-Induced Phase Stabilization and Enhanced Thermal Stability of κ-Ga₂O₃ Grown by Mist Chemical Vapor Deposition

Kang

Lee

et al. 2021

ACS Omega

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Tin (Sn)-doped orthorhombic gallium oxide (κ-Ga 2 O 3 ) films were grown on (0001) sapphire by mist chemical vapor deposition. It is known that κ-Ga 2 O 3 is more stable than α-Ga 2 O 3 (corundum) but less stable than β-Ga 2 O 3 (monoclinic). This thermodynamic stability means an optimal growth temperature (T g ) of the κ-phase (600−650 °C) is also in between the two. At first, it was observed that Sn doping induced the κ-phase during the growth of the β-phase (T g = 700 °C). Interestingly, Sn could also promote the κ-phase even under the growth condition that strongly favors the α-phase (T g = 450 °C). The postgrowth annealing tests at 800−1000 °C showed that the thermal stability of the κ-phase depends on the Sn concentration. The higher the Sn concentration, the more stable the phase. The one with the highest Sn content showed no phase transition from κ to β after annealing at 800, 900, and 1000 °C for 30 min each. This enhancement of thermal stability promises more reliable high-power and high-frequency devices for which κ-Ga 2 O 3 is suitable. Although there was no correlation between Sn-induced phase stabilization and the crystal quality, cathodoluminescence revealed that increasing Sn concentration led to the strong suppression of the radiative recombination at 340 nm from the vacancy-related donor− acceptor pairs. This observation suggests that the phase stabilization by Sn could be related to a specific Ga site Sn replaces in the orthorhombic structure.

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Origin of Red Emission in β‐Ga₂O₃ Analyzed by Cathodoluminescence and Photoluminescence Spectroscopy

Cited by 28 publications

References 30 publications

Correlation between deep-level defects and functional properties of β-(SnxGa1-x)2O3 on Si photodetectors

Correlation between deep-level defects and functional properties of β-(SnxGa1-x)2O3 on Si photodetectors

High Figure‐of‐Merit Gallium Oxide UV Photodetector on Silicon by Molecular Beam Epitaxy: A Path toward Monolithic Integration

Sn-Induced Phase Stabilization and Enhanced Thermal Stability of κ-Ga₂O₃ Grown by Mist Chemical Vapor Deposition

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Origin of Red Emission in β‐Ga2O3 Analyzed by Cathodoluminescence and Photoluminescence Spectroscopy

Cited by 28 publications

References 30 publications

Correlation between deep-level defects and functional properties of β-(SnxGa1-x)2O3 on Si photodetectors

Correlation between deep-level defects and functional properties of β-(SnxGa1-x)2O3 on Si photodetectors

High Figure‐of‐Merit Gallium Oxide UV Photodetector on Silicon by Molecular Beam Epitaxy: A Path toward Monolithic Integration

Sn-Induced Phase Stabilization and Enhanced Thermal Stability of κ-Ga2O3 Grown by Mist Chemical Vapor Deposition

Contact Info

Product

Resources

About

Origin of Red Emission in β‐Ga₂O₃ Analyzed by Cathodoluminescence and Photoluminescence Spectroscopy

Sn-Induced Phase Stabilization and Enhanced Thermal Stability of κ-Ga₂O₃ Grown by Mist Chemical Vapor Deposition