α/β phase junction Ga2O3 based high-performance self-powered deep ultraviolet photodetectors with Ti3C2/Ag nanowire hybrid conductive electrode

Photoelectrochemical properties of self-powered corundum-structured Ga2O3 nanorod array/fluorine-doped SnO2 photodetectors modulated by precursor concentrations

“…Among polymorphs of Ga 2 O 3 , corundum-structured Ga 2 O 3 (α-Ga 2 O 3 ) and monoclinic Ga 2 O 3 (β-Ga 2 O 3 ) are usually utilized as photosensitive materials [1,2,. However, in comparison to the most stable β-Ga 2 O 3 , metastable-phase α-Ga 2 O 3 has lower fabrication temperature [1,2,[16][17][18][19][20][21][22][23][24][25][26][27][28][29][30]. Therefore, α-Ga 2 O 3 based solar-blind UV photodetectors have been paid more attention in recent studies [2,[16][17][18][19][20][21][22][23][24][25][26][27][28][29][30].…”

“…However, in comparison to the most stable β-Ga 2 O 3 , metastable-phase α-Ga 2 O 3 has lower fabrication temperature [1,2,[16][17][18][19][20][21][22][23][24][25][26][27][28][29][30]. Therefore, α-Ga 2 O 3 based solar-blind UV photodetectors have been paid more attention in recent studies [2,[16][17][18][19][20][21][22][23][24][25][26][27][28][29][30]. In particularly, massive researches have been focused on self-powered α-Ga 2 O 3 -nanorod-array-based photodetectors on fluorine-doped SnO 2 (FTO), because of working in a photovoltaic mode without external biases and easy fabrication by hydrothermal and thermal annealing processes [2,[16][17][18][19][20][21][22][23][24][25][26][27][28]…”

“…The sample prepared for 18 h showed a lower dark current density of 2.4 μA cm −2 , higher responsivity of 1.2 mA W −1 at 230 nm at 0 V, and faster response speed of 0.06 s (decay time) [24]. Besides, α-Ga 2 O 3 /α-GaOOH, Al 2 O 3 /α-Ga 2 O 3 , α/β phase junction, ZnS/α-Ga 2 O 3 or Cu 2 O/α-Ga 2 O 3 heterojunctions were also designed to realize self-powered solar-blind UV photodetectors [12,19,20,23,26,27,30]. Guo et al investigated different annealing temperatures and annealing time to controllably realize Ga 2 O 3 nanorod arrays [12,26].…”

“…The heterojunction showed a faster response speed of 0.06 s at 254 nm at 0 V [19]. Through modulating annealing temperature, annealing time, growth time or constructing heterojunctions, the largest responsivity can reach 101.5 mA W −1 [ [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30]. However, the decay time of self-powered α-Ga 2 O 3 photodetectors should be further improved to develop the optoelectronic applications of Ga 2 O 3 based photodetectors, such as imaging, computing, communication and logic circuit .…”

“…It is noteworthy that the reported precursor concentrations of gallium nitrate (Ga(NO 3 ) 3 ) aqueous solutions are mostly considered between 0.01 and 0.06 M [12,[15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31]33]. To be well compared, herein, α-Ga 2 O 3 nanorod arrays with different precursor concentrations ranging from 0.01 to 0.06 M have been grown on FTO by hydrothermal and thermal annealing processes.…”