High Sensitivity Low-Temperature Hydrogen Sensors Based on SnO2/κ(ε)-Ga2O3:Sn Heterostructure

Abstract

The structural and gas-sensitive properties of n-N SnO2/κ(ε)-Ga2O3:Sn heterostructures were investigated in detail for the first time. The κ(ε)-Ga2O3:Sn and SnO2 films were grown by the halide vapor phase epitaxy and the high-frequency magnetron sputtering, respectively. The gas sensor response and speed of operation of the structures under H2 exposure exceeded the corresponding values of single κ(ε)-Ga2O3:Sn and SnO2 films within the temperature range of 25–175 °C. Meanwhile, the investigated heterostructures demonstrated a low response to CO, NH3, and CH4 gases and a high response to NO2, even at low concentrations of 100 ppm. The current responses of the SnO2/κ(ε)-Ga2O3:Sn structure to 104 ppm of H2 and 100 ppm of NO2 were 30–47 arb. un. and 3.7 arb. un., correspondingly, at a temperature of 125 °C. The increase in the sensitivity of heterostructures at low temperatures is explained by a rise of the electron concentration and a change of a microrelief of the SnO2 film surface when depositing on κ(ε)-Ga2O3:Sn. The SnO2/κ(ε)-Ga2O3:Sn heterostructures, having high gas sensitivity over a wide operating temperature range, can find application in various fields.

High-speed performance self-powered short wave ultraviolet radiation detectors based on κ(ε)-Ga2O3

“…The SI-GaN was a template for the κ(ε)-Ga 2 O 3 layer. At the second step, a κ(ε)-Ga 2 O 3 layer was deposited on the SI-GaN by the HVPE, employing a hot-wall home-made reactor providing high thickness and properties homogeneity on large areas [11,20,22] . Vapor phase GaCl and O 2 were utilized as precursors for elemental Ga and oxygen.…”

“…Such defects in the HVPE κ(ε)-Ga 2 O 3 layers were investigated by our group in detail in Ref. [20], however, their nature has not been definitively established yet.…”

β-Ga2O3 Schottky Barrier Diode with Ion Beam Sputter-Deposited Semi-Insulating Layer

“…To date, Schottky barrier diodes (SBDs) and field effect transistors (FETs) have been developed in a variety of designs, with lateral and vertical transport [28,33,34]. In addition, among the known five different phases of gallium oxide [35], which are widely studied mainly for the development of various detectors [36,37], β-Ga 2 O 3 is the most thermodynamically stable polymorph, which significantly expands the methods of material modification [38]. In addition to power electronics, stable β-Ga 2 O 3 and metastable αand κ(ε)-Ga 2 O 3 polymorphs are being actively investigated for the development of solar-blind shortwave UV detectors and gas sensors.…”