(In_xGa_1−x)₂O₃ Thin Film Based Solar‐Blind Deep UV Photodetectors with Ultra‐High Detectivity and On/Off Current Ratio

Abstract

This work reports the fabrication of high performance solar‐blind deep‐UV photodetectors using (InxGa1−x)2O3 thin films grown on Al2O3 (0001) substrates. The In contents in (InxGa1−x)2O3 are controlled at x = 0, 0.1 and 0.2, whereas a higher In content leads to phase segregation of Ga2O3 and In2O3. The bandgaps of (InxGa1−x)2O3 films are tuned from 4.93 eV for Ga2O3 to 4.67 eV for (In0.2Ga0.8)2O3. Schottky‐type photodetectors based on metal−semiconductor−metal structure were fabricated. The (In0.1Ga0.9)2O3 photodetector is highly sensitive to solar‐blind UV spectrum and achieves a large on/off current ratio of over 108, a remarkable specific detectivity of 4.5 × 1016 Jones with a prominent responsivity of 23.3 A W−1. Such enhanced performance compared to Ga2O3 is associated with In modulated optical and electronic properties. High‐resolution X‐ray photoemission spectroscopy was used to study the interfacial electronic structure at the semiconductor−metal interface. A large Schottky barrier height of 1.31 eV was found for (In0.1Ga0.9)2O3 devices, accounting for the low dark current. More importantly, the incorporation of In introduces In 4d states hybridizing with O 2p at top of the valence band of (In0.1Ga0.9)2O3, which increases the optical absorption to generate a higher density of photocarriers, and therefore results in greater photocurrents.

Indium doping-assisted monolayer Ga2O3 exfoliation for performance-enhanced MOSFETs

“…49,50 At present, In-doping is available experimentally, which guarantees doping feasibility in practical implementation. 32,33,51,52…”

“…49,50 At present, In-doping is available experimentally, which guarantees doping feasibility in practical implementation. 32,33,51,52 sition in In-O bonds after doping. All In-O bonds are lengthened compared with the pristine Ga-O bonds due to larger In ionic radius, as listed in Table 1.…”

“…At the IIIA group, the In atom shares similar outer electron arrangement with Ga atom and possesses larger atomic radius, which can be substitutionally doped in β-Ga 2 O 3 and has been well investigated at theoretical and experimental aspects in previous studies. 18,32,33 The enlarged In-O bonds are expected to weaken the In-O bond intensity and reduce the exfoliation energy, thus making it easy and efficient to obtain ML Ga 2 O 3 . To verify this conjecture, herein, we use first-principles calculation method to evaluate the ML Ga 2 O 3 exfoliation efficiency with the assistance of In-doping, and the doping influence on stability, structural, and electronic properties are systematically studied.…”

Fracture toughness and critical thickness of β-(InxGa1−x)2O3/Ga2O3 by first principles

“…[1][2][3][4][5][6][7] Ga 2 O 3 can exist in five polymorphs (a, b, g, d, and e), and b-Ga 2 O 3 is identified as the most stable structure with promising attributes, especially its ultra-wide bandgap of B4.8 eV and high critical electric field strength of 8 MV cm À1 . [8][9][10][11] Recent studies have demonstrated the use of (Al x Ga 1Àx ) 2 O 3 and (In x Ga 1Àx ) 2 O 3 ternary alloys for deep ultraviolet photodetectors, [12][13][14][15][16] showing that the properties of the b-Ga 2 O 3 material can be engineered through incorporation of other elements to finely tune the required device performance. Similar work has also extended into some other Ga 2 O 3 ternary and quaternary alloys, including (B x Ga 1Àx ) 2 O 3 and (Al x In y-Ga 1ÀxÀy ) 2 O 3 alloys.…”

AlInGaN nanocrystal seeded growth of weak p-type β-(In0.1Ga0.9)2O3 nanowires and nanobelts

“…A good photodetection capability at detection wavelengths from 255 to 350 nm is observed in (In x Ga 1− x ) 2 O 3 -based photodetectors, with a photoresponsivity of 10 −1 –10 2 A W −1 and a detectivity of ∼10 11 –10 16 Jones. 7–9 An improvement of the electron transport is demonstrated in In-incorporated oxides due to a reduction of the electron effective mass induced by the large spatial spread of the In 5s orbital with a large overlap. 5,10–13 An In-induced phase-change characteristic is also observed in (In x Ga 1− x ) 2 O 3 -based materials, and indicates a potential in the fabrication of a phase-change random access memory using (In x Ga 1− x ) 2 O 3 alloys.…”