The effect of annealing on the properties of Ga2O3 anodic films

The effect of annealing and oxygen plasma on the electrical characteristics of gallium oxide films has been investigated. Ga₂O₃ films with thicknesses of 200–300 nm were formed by the anodic oxidation of n-GaAs wafers with the donor concentration N _d = (1–2) × 10¹⁶ cm⁻³. It is shown that, after annealing at 900°C for 30 min, the gallium arsenide films contain only the β Ga₂O₃ phase. The effect of the duration of oxygen plasma treatment prior to annealing on the nucleation of β-phase crystallites with different orientations has been studied. It has been established that the electrical conductivity of the Ga₂O₃ films can be managed by annealing and variation in the duration of oxygen plasma treatment. It is shown that the response of the V/Ni-GaAs-Ga₂O₃-V/Ni structure to a mixture exhaled by a person depends on the value and sign of the potential on the control electrode.     

Properties of TiO2 films on silicon substrate

Influence of the substrate material and the effect of oxygen plasma on the microprofile and electrical properties of TiO₂ films deposited by radio-frequency magnetron sputtering are studied. It is shown that the most continuous films with the smallest roughness are obtained when deposited onto silicon substrates. The change in the capacitance-voltage and conductance-voltage characteristics of the structures upon their exposure to oxygen plasma is accounted for by the diffusion of oxygen atoms across the titanium-dioxide film and by the appearance of a SiO₂ layer at the Si-TiO₂ interface.     

Effect of Ultraviolet Radiation and Electric Field on the Conductivity of Structures Based on α- and ε-Ga2O3

Semiconductors - The effect of ultraviolet radiation and a strong electric field on the conductivity of structures based on two types of polymorphic gallium-oxide films is studied. Both types of...     

Effect of annealing in argon on the properties of thermally deposited gallium-oxide films

The effect of the annealing temperature on the I–V, C–I, and G–V characteristics and transparency of gallium-oxide films is investigated. The films are fabricated by the thermal evaporation of Ga₂O₃ powder on n-GaAs wafers. It is shown that the films which are amorphous after deposition crystallize upon annealing at temperatures T _an ≥ 800°C. The electrical characteristics and photoresponse of the V/Ni-GaAs-GaAs-Ga _x O _y -V/Ni samples to visible radiation depend on the structure and phase composition of the films.     

Effect of carbon monoxide on the capacitance-voltage characteristics of Pd-SiO<Subscript>2</Subscript>-Si MOS diodes

The effect of carbon monoxide on the capacitance-voltage characteristics of metal-oxide-semiconductor diodes of the Pd-SiO₂-n-Si type and the time dependences of changes in the capacitance at fixed diode biases have been investigated. The change in the capacitance in a CO-air gas mixture, in contrast to other reducing gases, is nonmonotonic. During exposure to a gas atmosphere, the capacitance-voltage characteristics first shift to higher positive biases, then regain their initial values, and finally shift to lower biases. A sharp decrease in the capacitance during the first several seconds of a gas pulse is followed by a slower increase in capacitance to a new steadystate value, which depends on the carbon monoxide concentration. The results are explained taking into account the bridge and linear types of CO adsorption on a SiO₂ surface.     

Effect of deep impurity on electric characteristics of epitaxial GaAs structures

The electric characteristics of the p ⁺-i-n ⁺ structures are analyzed for two types of GaAs epitaxial layers: the structures with an i layer based on undoped GaAs and an i layer based on GaAs:Cr. The forward currents of the first-type diodes are caused by recombination in the space-charge region. The reverse I–V characteristics at the voltages to 10–15 V are determined by the component of the generation current. At |U| > 20 V, the current growth is caused by the Poole-Frenkel effect, which is replaced by electron tunneling through the potential-barrier top with increasing the voltage as a result of the electron-phonon interaction. The forward branches of the I–V characteristics of the p ⁺-i-n ⁺ diodes with the i layer based on GaAs:Cr are explained by the unipolar injection in the semiconductor, which is replaced by the bipolar injection with increasing the voltage. The reverse I–V characteristics are linear in the range of 1–15 V; at |U| > 20 V, an increase in current is caused by the impact ionization.     

Solid-state image converters on the basis of the GaAs/ZnS structures

Semiconductors - Emission-voltage characteristics and frequency dependences of the luminescence intensity of electroluminescent capacitors on the basis of the ZnS:(Cu,Al) phosphor are studied. The...     

Mechanism of formation of the response of a hydrogen gas sensor based on a silicon MOS diode

Experimental data on the dependence of the flat-band voltage and relaxation time for the capacitance of the space-charge region in an MOS diode (Pd-SiO₂-n-Si) on the hydrogen concentration in a hydrogen/air gaseous mixture are discussed. It is assumed that variation in the flat-band voltage U _fb in an MOS structure with the thickness d = 369 nm subjected to a hydrogen/air gaseous mixture can be accounted for by the formation of dipoles in the Pd-SiO₂ gap due to polarization of hydrogen atoms (H _a ). An analytical expression describing the dependence of variation in the flat-band voltage ΔU _fb on the hydrogen concentration \(n_{H_2 } \) was derived. In MOS structures with d ≤ 4 nm (or MOS diodes), the value of ΔU _fb is mainly controlled by passivation of the centers responsible for the presence of the surface acceptor-type centers at the SiO₂-n-Si interface by hydrogen atoms. Analytical expressions describing the dependences of ΔU _fb and the capacitance relaxation time in the space-charge region on \(n_{H_2 } \) are derived. The values of the density of adsorption centers and the adsorption heat for hydrogen atoms at the Pd-SiO₂ and SiO₂-n-Si interfaces are found.     

Influence of Electrodes on the Parameters of Solar-Blind Detectors of UV Radiation

Semiconductors - The influence of the topology of electrodes on the electrical and photoelectric characteristics of metal–semiconductor–metal structures is studied. Gallium-oxide films...     

The Effect of Operating Modes on the Response of Ammonia Sensors Based on Tin Dioxide Films

Technical Physics Letters - The influence of operating modes on the response of ammonia sensors based on tin dioxide films has been studied. Samples have been obtained as a result of high-frequency...