In this paper, we report the direct growth of ultra-wide bandgap GeO2 film on the m-plane sapphire substrate by pulsed laser deposition. Raman scattering and x-ray diffraction measurements confirm that the obtained GeO2 film has a (001)-oriented rutile structure mixed with the amorphous phase, and the film has an out-of-plane strain of –0.28% along the c direction. Transmittance spectra and x-ray photoelectron spectroscopy measurements determine that the transparent GeO2 film has an ultra-wide bandgap of about 5.1 eV. Room temperature photoluminescence spectrum exhibits a broad blue–green emission band dominated by two peaks at about 2.4 and 2.8 eV. With the temperature decreasing to 21 K, the peak intensities increase exponentially accompanied by a slight blue-shift in the peak position. We believe that these findings will pave the way for applications of the wide-bandgap GeO2 film in power and optoelectronic devices.
References
1.
J. Y.
Tsao
, S.
Chowdhury
, M. A.
Hollis
, D.
Jena
, N. M.
Johnson
, K. A.
Jones
, R. J.
Kaplar
, S.
Rajan
, C. G.
Van de Walle
, E.
Bellotti
, C. L.
Chua
, R.
Collazo
, M. E.
Coltrin
, J. A.
Cooper
, K. R.
Evans
, S.
Graham
, T. A.
Grotjohn
, E. R.
Heller
, M.
Higashiwaki
, M. S.
Islam
, P. W.
Juodawlkis
, M. A.
Khan
, A. D.
Koehler
, J. H.
Leach
, U. K.
Mishra
, R. J.
Nemanich
, R. C. N.
Pilawa-Podgurski
, J. B.
Shealy
, Z.
Sitar
, M. J.
Tadjer
, A. F.
Witulski
, M.
Wraback
, and J. A.
Simmons
, “Ultrawide-bandgap semiconductors: Research opportunities and challenges
,” Adv. Electron. Mater.
4
, 1600501
(2018
).2.
F.
Lloret
, D.
Eon
, E.
Bustarret
, F.
Donatini
, and D.
Araujo
, “Selectively boron doped homoepitaxial diamond growth for power device applications
,” Appl. Phys. Lett.
118
, 023504
(2021
).3.
M.
Kneissl
, T.-Y.
Seong
, J.
Han
, and H.
Amano
, “The emergence and prospects of deep-ultraviolet light-emitting diode technologies
,” Nat. Photonics
13
, 233
–244
(2019
).4.
D.
Guo
, Y.
Su
, H.
Shi
, P.
Li
, N.
Zhao
, J.
Ye
, S.
Wang
, A.
Liu
, Z.
Chen
, C.
Li
, and W.
Tang
, “Self-powered ultraviolet photodetector with superhigh photoresponsivity (3.05A/W) based on the GaN/Sn:Ga2O3 pn junction
,” ACS Nano
12
, 12827
–12835
(2018
).5.
S.
Chae
, K.
Mengle
, K.
Bushick
, J.
Lee
, N.
Sanders
, Z.
Deng
, Z.
Mi
, P. F. P.
Poudeu
, H.
Paik
, J. T.
Heron
, and E.
Kioupakis
, “Toward the predictive discovery of ambipolarly dopable ultra-wide-band-gap semiconductors: The case of rutile GeO2
,” Appl. Phys. Lett.
118
, 260501
(2021
).6.
M.
Stapelbroek
and B. D.
Evans
, “Exciton structure in the U.V.-absorption edge of tetragonal GeO2
,” Solid State Commun.
25
, 959
–962
(1978
).7.
C. A.
Niedermeier
, K.
Ide
, T.
Katase
, H.
Hosono
, and T.
Kamiya
, “Shallow valence band of rutile GeO2 and P-type doping
,” J. Phys. Chem. C
124
, 25721
–25728
(2020
).8.
K. A.
Mengle
, S.
Chae
, and E.
Kioupakis
, “Quasiparticle band structure and optical properties of rutile GeO2, an ultra-wide-band-gap semiconductor
,” J. Appl. Phys.
126
, 085703
(2019
).9.
S.
Chae
, J.
Lee
, K. A.
Mengle
, J. T.
Heron
, and E.
Kioupakis
, “Rutile GeO2: An ultrawide-band-gap semiconductor with ambipolar doping
,” Appl. Phys. Lett.
114
, 102104
(2019
).10.
K.
Bushick
, K. A.
Mengle
, S.
Chae
, and E.
Kioupakis
, “Electron and hole mobility of rutile GeO2 from first principles: An ultrawide-bandgap semiconductor for power electronics
,” Appl. Phys. Lett.
117
, 182104
(2020
).11.
S.
Chae
, K. A.
Mengle
, R.
Lu
, A.
Olvera
, N.
Sanders
, J.
Lee
, P. F. P.
Poudeu
, J. T.
Heron
, and E.
Kioupakis
, “Thermal conductivity of rutile germanium dioxide
,” Appl. Phys. Lett.
117
, 102106
(2020
).12.
S.
Witanachchi
and P. J.
Wolf
, “Activated reactive laser deposition of GeO2 films
,” J. Appl. Phys.
76
, 2185
(1994
).13.
N.
Terakado
and K.
Tanaka
, “Solids photo-induced phenomena in sputtered GeO2 films
,” J. Non-Cryst. Solids
351
, 54
(2005
).14.
A.
Chiasera
, C.
Macchi
, S.
Mariazzi
, S.
Valligatla
, L.
Lunelli
, C.
Pederzolli
, D. N.
Rao
, A.
Somoza
, R. S.
Brusa
, and M.
Ferrari
, “CO2 laser irradiation of GeO2 planar waveguide fabricated by rf-sputtering
,” Opt. Mater. Express
3
, 1561
(2013
).15.
N. R.
Murphy
, J. T.
Grant
, L.
Sun
, J. G.
Jones
, R.
Jakubiak
, V.
Shutthanandan
, and C. V.
Ramana
, “Correlation between optical properties and chemical composition of sputter-deposited germanium oxide (GeOx) films
,” Opt. Mater.
36
, 1177
(2014
).16.
S.
Chae
, H.
Paik
, N. M.
Vu
, E.
Kioupakis
, and J. T.
Heron
, “Epitaxial stabilization of rutile germanium oxide thin film by molecular beam epitaxy
,” Appl. Phys. Lett.
117
, 072105
(2020
).17.
H.
Takane
and K.
Kaneko
, “Establishment of a growth route of crystallized rutile GeO2 thin film (≧1 μm/h) and its structural properties
,” Appl. Phys. Lett.
119
, 062104
(2021
).18.
F. B.
Zhang
, K.
Saito
, T.
Tanaka
, M.
Nishio
, and Q. X.
Guo
, “Structural and optical properties of Ga2O3 films on sapphire substrates by pulsed laser deposition
,” J. Cryst. Growth
387
, 96
–100
(2014
).19.
G.
Deng
, Y.
Huang
, Z.
Chen
, C.
Pan
, K.
Saito
, T.
Tanaka
, and Q.
Guo
, “Yellow emission from vertically integrated Ga2O3 doped with Er and Eu electroluminescent film
,” J. Lumin.
235
, 118051
(2021
).20.
G.
Deng
, K.
Saito
, T.
Tanaka
, and Q.
Guo
, “Improvement of sensing sensitivity based on green emissions from Er-doped (AlGa)2O3 films
,” J. Lumin.
232
, 117879
(2021
).21.
J.
Moulder
, W.
Stickle
, P.
Sobol
, and K.
Bomben
, Handbook of X‐Ray Photoelectron Spectroscopy
, edited by J.
Chastian
(PerkinElmer Corporation
, Eden Prairie, MN
, 1993
), p. 92
.22.
R.
Kaindl
, D. M.
Többens
, S.
Penner
, T.
Bielz
, S.
Soisuwan
, and B.
Klötzer
, “Quantum mechanical calculations of the vibrational spectra of quartz- and rutile-type GeO2
,” Phys. Chem. Miner.
39
, 47
–55
(2012
).23.
M.
Madon
, P.
Gillet
, C.
Julien
, and G. D.
PriceA
, “Vibrational study of phase transitions among the GeO2 polymorphs
,” Phys. Chem. Miner.
18
, 7
–18
(1991
).24.
A.
Sanson
, G. S.
Pokrovski
, M.
Giarola
, and G.
Mariotto
, “Vibrational dynamics of rutile-type GeO2 from micro-Raman spectroscopy experiments and first-principles calculations
,” Europhys. Lett.
109
, 26007
(2015
).25.
A.
Lignie
, P.
Hermet
, G.
Fraysse
, and P.
Armand
, “Raman study of α-quartz-type Ge1−xSixO2 (0 < x ≤ 0.067) single crystals for piezoelectric applications
,” RSC Adv.
5
, 55795
–55800
(2015
).26.
W. H.
Baur
and A. A.
Khan
, “Ruffle-type compounds. IV. SiO2, GeO2 and a comparison with other Ruffle-type structures
,” Acta Crystallogr., Sect. B
27
, 2133
–2139
(1971
).27.
S.
Zhao
, Z.
Fu
, and Q.
Qin
, “A solid-state electrolyte lithium phosphorus oxynitride film prepared by pulsed laser deposition
,” Thin Solid Films
415
, 108
–113
(2002
).28.
H.
Yanagi
, C.
Sato
, Y.
Kimura
, I.
Suzuki
, T.
Omata
, T.
Kamiya
, and H.
Hosono
, “Widely bandgap tunable amorphous Cd–Ga–O oxide semiconductors exhibiting electron mobilities ≥ 10 cm2 V−1 s−1
,” Appl. Phys. Lett.
106
, 082106
(2015
).29.
J.
Bruncko
, A.
Vincze
, M.
Netrvalova
, P.
Šutta
, D.
Hasko
, and M.
Michalka
, “Annealing and recrystallization of amorphous ZnO thin films deposited under cryogenic conditions by pulsed laser deposition
,” Thin Solid Films
520
, 866
–870
(2011
).30.
S. S.
Kumar
, E. J.
Rubio
, M.
Noor-A-Alam
, G.
Martinez
, S.
Manandhar
, V.
Shutthanandan
, S.
Thevuthasan
, and C. V.
Ramana
, “Structure, morphology, and optical properties of amorphous and nanocrystalline gallium oxide thin films
,” J. Phys. Chem. C
117
, 4194
–4200
(2013
).31.
F.
Zhang
, K.
Saito
, T.
Tanaka
, M.
Nishio
, M.
Arita
, and Q.
Guo
, “Wide bandgap engineering of (AlGa)2O3 films
,” Appl. Phys. Lett.
105
, 162107
(2014
).32.
G.
Deng
, F.
Zhang
, K.
Saito
, T.
Tanaka
, M.
Arita
, and Q.
Guo
, “Enhanced green emission from Er-doped (AlGa)2O3 films grown by pulsed laser deposition
,” Jpn. J. Appl. Phys.
59
, 051007
(2020
).33.
A.
Samanta
, M.
Jain
, and A. K.
Singh
, “Ultra-sensitive pressure dependence of bandgap of rutile-GeO2 revealed by many body perturbation theory
,” J. Chem. Phys.
143
, 064703
(2015
).34.
T.
Lange
, W.
Njoroge
, H.
Weis
, M.
Beckers
, and M.
Wuttig
, “Physical properties of thin GeO2 films produced by reactive DC magnetron sputtering
,” Thin Solid Films
365
, 82
–89
(2000
).35.
S. L.
Shinde
and K. K.
Nanda
, “Thermal oxidation strategy for the synthesis of phase-controlled GeO2 and photoluminescence characterization
,” CrystEngComm
15
, 1043
–1046
(2013
).36.
A.
Trukhin
, M.
Kink
, Y.
Maksimov
, J.
Jansons
, and R.
Kink
, “Luminescence of GeO2 glass, rutile-like and α-quartz-like crystals
,” J. Non-Cryst. Solids
352
, 160
–166
(2006
).37.
V. B.
Mykhaylyk
, H.
Kraus
, V.
Kapustianyk
, and M.
Rudko
, “Low temperature scintillation properties of Ga2O3
,” Appl. Phys. Lett.
115
, 081103
(2019
).38.
Z.
Liu
, Y.
Huang
, X.
Yi
, B.
Fu
, G.
Yuan
, J.
Wang
, J.
Li
, and Y.
Zhang
, “Analysis of photoluminescence thermal quenching: Guidance for the design of highly effective p-type doping of nitrides
,” Sci. Rep.
6
, 32033
(2016
).39.
Y. P.
Varshni
, “Temperature dependence of the energy gap in semiconductors
,” Physics
34
, 149
–154
(1967
).© 2021 Author(s). Published under an exclusive license by AIP Publishing.
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