Ultrawide-bandgap (6.14 eV) (AlGa)2O3/Ga2O3 heterostructure designed by lattice matching strategy for highly sensitive vacuum ultraviolet photodetection

Abstract

One judiciously designed strategy of utilizing an ultrathin but conductive Ga 2 O 3 :Si nanolayer to prepare (AlGa) 2 O 3 crystalline film is demonstrated. Benefiting from the existence of Ga 2 O 3 :Si nanolayer, a high-quality (Al 0.68 Ga 0.32 ) 2 O 3 sesquioxide film with 68 at.% aluminum was epitaxially grown on sapphire substrates, which was characterized by high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy and X-ray diffraction. Its bandgap was broadened to 6.14 eV, and a vacuum ultraviolet (VUV) (AlGa) 2 O 3 /Ga 2 O 3 :Si photodetector was subsequently fabricated. The detector exhibits a pretty high on-off ratio of about 10 3 , an open-circuit voltage of 1.0 V and a responsivity of 8.1 mA W −1 at 0 V bias voltage. The performances imply that the proposed strategy is valuable for improving the quality and also adjusting the bandgap of (AlGa) 2 O 3 sesquioxides, which is expected to facilitate their application in VUV photodetection.

Unintentional doping effect in Si-doped MOCVD β-Ga2O3 films: Shallow donor states

“…β-Ga 2 O 3 is an important candidate semiconductor material for next-generation power electronic devices and solar-blind ultraviolet photodetectors, due to its ultra-wide bandgap, high critical electric breakdown field, and large Baliga's figure of merit [1-4]. In the past few years, high-performance β-Ga 2 O 3 -based devices including Schottky barrier diode (SBD) [5,6], pn diode [7,8], metal-oxide-semiconductor field-effect transistor (MOSFET) [9,10], and photodetector [11][12][13][14][15][16] have been quickly demonstrated, in which high-quality epitaxial films are of crucial importance [6,7,9]. One of the most important methods to obtain epitaxial β-Ga 2 O 3 films is metalorganic chemical vapor deposition (MOCVD), thanks to its fast growth rate, large area homogeneity, and superb film quality [17][18][19][20].…”

Strong Electron–Phonon Coupling in β-Ga2O3: A Huge Broadening of Self-Trapped Exciton Emission and a Significant Red Shift of the Direct Bandgap

“…Gallium oxide (Ga 2 O 3 ) has attracted more and more attention in recent years because of its ultrawide bandgap and a corresponding ultrahigh breakdown field. − Among them, monoclinic gallium oxide (β-Ga 2 O 3 ) has long been a focus, − and to promote the development of β-Ga 2 O 3 -based optoelectronic devices, it is undoubtedly significant to conduct a deep exploration on its optoelectric properties.…”

Extremely High Photovoltage (3.16 V) Achieved in Vacuum-Ultraviolet-Oriented van der Waals Photovoltaics

“…Compared with the VUV photodetectors with p-i-n structure reported previously, the photovoltaic performance of the prepared device is significantly improved (Table S1). ,,,,, By analyzing Raman scattering spectroscopy, the degree of how doping modulates the Fermi level of graphene is extracted. And combined with the photoelectric output of the graphene device, the increase mechanism of V OC of the device is elucidated.…”

“…Getting these two figures of merit improved is an urgent and meaningful need not only for photocells but also for a better performance of the photodetectors operating in current or voltage mode. In previous studies on AlN-based photovoltaic devices, n-type 4H-SiC has been proved as an ideal substrate for heteroepitaxial AlN films and an excellent electron transport layer for devices owing to the advantages of high lattice matching and small electron affinity which provides large contact potential difference. − In previous reports, metals with large work functions such as Pt were usually used as semitransparent window layers to collect photogenerated holes, − but their transmittance to VUV light is limited, which is not conducive to the photoexcitation of absorbing layers. Therefore, optimizing the hole transport layer can be an effective way to further improve the photovoltaic performance of the device.…”