Flame Detection by a β-Ga₂O₃-Based Sensor

Abstract

An oxide semiconductor of -Ga 2 O 3 has a natural solar-blind sensitivity due to its large bandgap of 4.8 eV. To evaluate its potential, a flame detector was fabricated using its conductive single crystal substrate applying a simple method without epitaxy and vacuum processes. The structure is a poly(3,4-ethylene dioxythiophene) complex with polystyrene sulfonic acid (PEDOT-PSS) Schottky contact/a semi-insulating layer of -Ga 2 O 3 /n-type region of -Ga 2 O 3 /an In ohmic contact. The spectral response of the detector exhibited a large 250-to-300-nm rejection ratio of 1:5 Â 10 4 and an external quantum efficiency of 18% at 250 nm. The device successfully detected a flame by distinguishing 1.5 nW/cm 2 solar-blind light from the flame under a strong fluorescent lamp illumination without any visible-cut filters. This result encourages the fabrication of practical -Ga 2 O 3 -based flame detectors.

Epitaxial growth of γ-Ga2O3 films by mist chemical vapor deposition

“…In recent, its nature of a wide-band-gap semiconductor has been rather attracting much attentions towards realizing active devices such as transparent field-effect transistors (FET) [2,3], UV sensors for flame detection [4], and next-generation high-power devices [5,6]. Compared with SiC and GaN in terms of high-power device applications, it is particularly advantageous that large and highquality Ga 2 O 3 single crystals can be synthesized by melt growth techniques such as floating zone [7], Czochralski [8], and edgedefined film-fed growth [9].…”

Growth characteristics of corundum-structured α-(Al Ga1−)2O3/Ga2O3 heterostructures on sapphire substrates

“…Recent achievements showing solar-blind photodetectors [2], Shottkybarrier diodes (SBDs) [3,4], and field-effect transistors (FETs) [5,6] have markedly accelerated the interest and research on this material. Among five crystal structures of Ga 2 O 3 (α, β, γ, δ, and ε) orthorhombic β-gallia-structured β-Ga 2 O 3 was reported to be the most stable phase from the thermodynamics [7,8].…”

Out-of-Band Measurement of LED-based Solar Blind UV Filters

“…Thus, an emitter in this region can be detected when it emits solar blind UV radiation, due to the complete absence of that radiation from the background (called the "blank background") [1][2][3][4]. UV detection has been widely applied, such as for identifying coronas surrounding high-voltage wires [5], the observation, identification, and tracking of space targets [6], fire alarms, and so on [7][8][9][10][11].…”