2912 results about "Photocurrent" patented technology

In one aspect, the present invention provides a silicon photodetector having a surface layer that is doped with sulfur inclusions with an average concentration in a range of about 0.5 atom percent to about 1.5 atom percent. The surface layer forms a diode junction with an underlying portion of the substrate. A plurality of electrical contacts allow application of a reverse bias voltage to the junction in order to facilitate generation of an electrical signal, e.g., a photocurrent, in response to irradiation of the surface layer. The photodetector exhibits a responsivity greater than about 1 A / W for incident wavelengths in a range of about 250 nm to about 1050 nm, and a responsivity greater than about 0.1 A / W for longer wavelengths, e.g., up to about 3.5 microns.

Effective differential dynamic range in a differential pixel detector is increased by avoiding saturation effects due to common mode contribution in optical energy to be detected. Photocurrent generated by each photodetector pair is directly integrated by an associated capacitor over an integration time T. Within time T, before either integrated capacitor voltage reaches Vsat for the photodetector, at least one of the capacitors is reset to a voltage such that the desired differential detector signal is still determinable. Reset may be generated externally or internally to the differential pixel detector.

A compact LADAR transmitting and receiving apparatus includes a pulse laser generating pulses of light; a transmitter collimating and directing the pulses of light toward a target; a receiver collecting reflected pulses of light, the reflected pulses of light having been reflected from the target, the receiver comprising a tapered fiber bundle; a sensor operatively connected to the tapered fiber bundle, where the sensor comprises a photosensitive region and outputs a photocurrent; an amplifier amplifying the photocurrent; and a power divider splitting the amplified photocurrent between a high gain channel and a low gain channel; a RF interface accepting the high gain channel, the low gain channel, and an undelayed sample of a pulse of light generated from the pulse laser as input; a processing unit accepting output from the RF interface; and a display unit displaying output from the processing unit.

A photoelectrochemical assay apparatus for determining chemical oxygen demand (COD) of a water sample which consists of a) a measuring cell for holding a sample to be analysed b) a titanium dioxide nanoparticle photoelectric working electrode and a counter electrode disposed in said cell, c) a UV light source adapted to illuminate the photoelectric working electrode d) control means to control the illumination of the working electrode e) potential measuring means to measure the electrical potential at the working and counter electrodes f) analysis means to derive a measure of oxygen demand from the measurements made by the potential measuring means. The method of determining chemical oxygen demand of a water sample, comprises the steps of a) applying a constant potential bias to a photoelectrochemical cell, containing a supporting electrolyte solution; b) illuminating the working electrode with a UV light source and recording the background photocurrent produced at the working electrode from the supporting electrolyte solution; c) adding a water sample, to be analysed, to the photoelectrochemical cell; d) illuminating the working electrode with a UV light source and recording the total photocurrent produced; e) determining the chemical oxygen demand of the water sample according to the type of degradation conditions employed. The determination may be under exhaustive degradation conditions, in which all organics present in the water sample are oxidised or under non-exhaustive degradation conditions, in which the organics present in the water sample are partially oxidised.

A method of and an apparatus for an electro-optical distance measurement in which a laser beam of a laser diode (1) is directed as an intensity modulated train of emitted light pulses onto an object, the reflected measurement pulse train (10) is detected by a light detector (6), which generates, in response to the detection of a measurement pulse train, a first photo-current component, a smaller portion of the intensity modulated pulse train is branched out as a reference pulse train and, after passing a known reference path, is also detected by the light detector (6), which generates in response to this detection a second photo current component, and the light detector converts the measurement pulses, together with a mixer pulse train generated by a local oscillator, into a comparatively low-frequency IF-region that determines, after a corresponding conversion, the measured distance.

A method for controlling the exposure of an active pixel array electronic still camera includes the steps of: integrating photocurrent in each pixel during an integration time period; collecting overflow charge from all pixels in the array during the integration time period; developing an overflow signal as a function of the overflow charge; and terminating the integration time period when the overflow signal exceeds a preset threshold level selected to represent a desired reference exposure level. Apparatus for performing the method of the present invention includes circuitry for integrating photocurrent in each pixel during a integration time period; circuitry for diverting and detecting overflow charge from all pixels in the array during the integration time period; circuitry for developing an overflow signal as a function of the overflow charge; and circuitry for terminating said integration time period when the overflow signal exceeds a preset threshold level selected to represent a desired reference exposure level.

A photodetector capable of normal incidence detection over a broad range of long wavelength light signals to efficiently convert infrared light into electrical signals. It is capable of converting long wavelength light signals into electrical signals with direct normal incidence sensitivity without the assistance of light coupling devices or schemes. In the apparatus, stored charged carriers are ejected by photons from quantum dots, then flow over the other barrier and quantum dot layers with the help of an electric field produced with a voltage applied to the device, producing a detectable photovoltage and photocurrent. The photodetector has multiple layers of materials including at least one quantum dot layer between an emitter layer and a collector layer, with a barrier layer between the quantum dot layer and the emitter layer, and another barrier layer between the quantum dot layer and the collector.

A rapid thermal processing (RTP) system including a transmission pyrometer monitoring the temperature dependent absorption of the silicon wafer for radiation from the RTP lamps at a reduced power level. A look-up table is created relating unnormalized values of photodetector photocurrents with wafer and radiant lamp temperatures. A calibrating step measures the photocurrent with known wafer and lamp temperatures and all photocurrents measured thereafter are accordingly normalized. The transmission pyrometer may be used for closed loop control for thermal treatments below 500° C. or used in the pre-heating phase for a higher temperature process including radiation pyrometry in closed loop control. The pre-heating temperature ramp rate may be controlled by measuring the initial ramp rate and readjusting the lamp power accordingly. Radiation and transmission pyrometers may be included in an integrated structure with a beam splitter dividing radiation from the wafer.