Abstract: A method for determining a concentration of a target gas in blood of a human or animal animate being. The method includes the steps of: generating electromagnetic excitation radiation having a carrier frequency, wherein the carrier frequency is selected such that the target gas and an absorbing gas absorb the excitation radiation, modulating an amplitude or the carrier frequency of the excitation radiation with a modulation frequency, illuminating an absorption path superficial to a skin of the animate being with the excitation radiation, generating a sound wave by an absorption of the excitation radiation in the absorption gas, and detecting at least one of an amplitude and a phase of the sound wave as a measure of a concentration of the target gas on the absorption path. Also provided is a photoacoustic sensor for determining a concentration of a target gas in blood of a human or animal animate being.

Abstract: A metal oxide semiconductor gas sensor and a method for production thereof. The sensor comprises a sensor-active metal oxide thin layer applied to a substrate, in contact with at least one electrode. The sensor-active metal oxide thin layer comprises a chromium/titanium oxide (CTO) layer with a thickness of about 10 nm to about 1 ?m. The chromium and titantium layers are applied over each other using thin layer technology and are subsequently tempered.

Abstract: A gas sensor includes a semiconductor substrate on which is disposed at least one field electrode, and advantageously a plurality of field electrodes. The field electrodes are disposed under a gas-sensitive semiconductor resistive film, with an insulator layer in between. The film, which may be in electrical contact with a pair of external electrodes, may comprise a metal oxide, such as for example SnO2, WO3, In2O3, Ga2O3, Cr2-xTixO3+z, or various organic semiconductors. The field electrodes produce an electric field acting on the semiconductor, and an electroadsorptive effect may occur when the thickness of the gas-sensitive film is on the order of the Debye length. In the case of the known gas-sensitive material SnO2, for example, the Debye length may be approximately 60 to 80 nm. An electric field produced in the body of the gas sensor may be effective up to the surface of the gas-sensitive film that is exposed to the gas, i.e., the films lying above the gate electrode do not screen the electric field.

Abstract: A metal oxide semiconductor gas sensor and a method for production thereof. The sensor comprises a sensor-active metal oxide thin layer applied to a substrate, in contact with at least one electrode. The sensor-active metal oxide thin layer comprises a chromium/titanium oxide (CTO) layer with a thickness of about 10 nm to about 1 &mgr;m. The chromium and titantium layers are applied over each other using thin layer technology and are subsequently tempered.