Showing papers on "Responsivity published in 1977"

InxGa1−xAsyP1−y/InP heterojunction photodiodes

Abstract: The photoelectronic properties of quaternary alloy heterojunction photodiodes made of liquid‐phase‐grown In0.88Ga0.12As0.25P0.75 layers deposited onto p‐doped InP substrates have been investigated experimentally and analytically. It is shown that a typical photodiode with a peak responsivity of 0.26 A/W (at 1.02 μm) has a quantum efficiency of ∼22% at 1.06 μm.

Piezoelectric polymer receiving arrays for ultrasonic applications

Abstract: Broadband ultrasonic detector elements each approximately 2 mm in diameter and multielement linear arrays have been constructed using commercially available polyvinylidene fluoride sheet 25 μm thick. Electrode and electrical lead patterns were deposited on both surfaces by vacuum evaporation. Poling was achieved by applying ∼2000 V across the electroded parts of the sheet while the temperature was cycled from room temperature to ∼120°C over a period of ∼1 h. The open‐circuit responsivity of the samples to ultrasound was measured in the frequency range of 300 kHz to 1 MHz with the samples freely immersed in water, with the array backed by a steel ref1ector plate, and with the array a distance away from the reflector plate. The measurements were performed with the elements connected to a preamplifier by means of a 50 Ω coaxial tube about 30 cm long. Since the capacitance of an element is about 8 pF, the measured responsivity of about −230 dB re 1 V/μPa was degraded considerably by the cable capacitance. The...

Detection of 10‐μ radiation with point‐contact Schottky diodes

Abstract: Point‐contact Schottky diodes have been used to detect 10.6‐μ radiation. Best results were obtained with n‐Ge/W contacts. These gave voltage responsivity about an order of magnitude larger than typical metal‐oxide‐metal point contacts under zero‐bias conditions, although with higher source impedance.

Stannic oxide, a new FIR detector material?

Abstract: We report on the strong bolometric response of doped stannic oxide single crystals to submillimeter radiation. As confirmed up to 120 kG, the magnetic field dependence of the bolometric response is negligible. The bolometer responsivity at zero frequency has been evaluated from the load curve and compared with the corresponding data of the Ge bolometer. The new detector has been used successfully in a magnetic field to detect the electron cyclotron resonance in InSb.

Ultraviolet enhanced responsivity of silicon photodiodes: an investigation.

Abstract: An enhancement of the responsivity of certain types of silicon photodetectors after exposure to uv radiation has been recently reported. Several possible mechanisms were investigated experimentally and ruled out on the basis of the results.

Chapter 3 InSb Submillimeter Photoconductive Detectors

Abstract: Publisher Summary The basic characteristics of the submillimeter detector do not change as they depend critically upon the purity of the available InSb, which is not improved upon. More attention is given to heterodyne techniques where it is shown that the insertion loss of the InSb mixer can be as low as 7 dB, which is substantially less than that of other readily available millimeter wave mixers. The performance is improved by a careful design of the element mounting to optimize the absorption of the radiation. In applications where the short response time is not required (as in most spectroscopy) an alternative method of obtaining a highly effective responsivity is to step up the impedance of the detector by means of a transformer cooled in the liquid helium. It is cooled to eliminate noise associated with its loss components.

Double-Junction Photosensitive Devices with High uv Responsivity

Abstract: This paper describes the design and the fabrication of silicon photodetectors with a broad banded response. The devices are featuring shallow (xj1≈0.1 µm) and deep (xj2≈5 µm) junctions which contribute to the photoresponse at short and long wavelengths, respectively. The shallow junction is generated by a special diffusion process employing a partially masking SiO2 layer. The double-junction principle can be extended to light-sensitive FET structures exhibiting an internal gain of about 104.

GaAs waveguide detectors for 1.06 μm

Abstract: GaAs electroabsorption avalanche photodiodes in n‐n+ GaAs waveguides have been used to detect the 1.06‐μm radiation from a Nd : YAG laser with a responsivity of 125 A/W and an internal quantum efficiency of 23%. The response at this wavelength is due to a combination of band‐to‐band and defect‐to‐band electroabsorption.

Thallium selenide infrared detector.

Abstract: The application of semiconducting thallium selenide for ir detection is described. A responsivity of 106 V/W and NEP of the order of 10−15 W/√Hz with a response time of 3 msec can be obtained by operating the detector at 1.5 K.

Instruments for detection of infrared laser radiation pulses based on the photon drag of carriers in semiconductors

Abstract: Fast-response uncooled far-infrared detectors were developed on the basis of the photon drag of carriers in semiconductors. The responsivity, time resolution, and noise immunity of these detectors were investigated from the point of view of optimization of these parameters. Detectors without (type FP) and with (type FPU) amplifiers were built and described. These were characterized by a high time resolution (≥7×10–10 sec), a wide power range (10–4×108 W), and a high degree of noise immunity. The detectors were calibrated for CO2 laser radiation. Two models with amplifiers (type FPU-50 and FPU-100) had a set of interchangeable detectors, which made it possible to measure radiation powers from 10 to 2×106 W with the same instrument.

Servoosystem driving method

Abstract: PURPOSE:Without changing a characteristic, i.e. transfer function itself of a servo-system, a responsivity is elevated by modifying input numerical command and without causing overshoot and other problems, control of positioning, etc. is performed quickly.

Fast-response pyroelectric crystal detector based on Ba0.25Sr0.75Nb2O6

Abstract: A study was made of the problems of using BaxSr1–xNb2O6 (BSN) crystals to measure high-power CO2 laser radiation of λ = 10.6 μ wavelength. An experimental investigation of BSN crystals with x = 0.25 yielded the characteristics of a pyroelectric detector of this type: responsivity 20 V/MW; response time 2 nsec; linear up to 3 MW/cm2; optical strength up to 9 MW/cm2. Pyroelectric detectors based on BSN crystals were used to detect and analyze the spatial and temporal structure of short high-power CO2 laser pulses.

New processes and materials for ultraviolet detection with solid state devices

Abstract: The three major effects that degrade external responsivity of silicon from the 1/Atheoretical curve for a quantum detector are: surface reflectance, surface recombination,and junction depth. Since the p -n junction must be very shallow, problems relating tosurface are further enhanced. MOS type of processing is necessary. HC1 oxides and numerousacid clean -ups are utilized in order to obtain a contamination free surface with low Qss levels. Stringent process controls such as CV shifts, spreading resistance measurements,thickness monitoring etc., are used to analyze the surface contaminations, surface mobilecharges, surface concentrations, junction depth, oxide thickness etc. Low surfaceconcentrations of 1018 atoms /cm3 are achieved by low temperature Boron Nitride depositions.This helps in reducing surface recombination. Shallow junction depths of the order of afew tenths of a micron are achieved by low temperature controlled diffusions. In order toimprove breakdown characteristics of these shallow junction devices, field plate and deepdiffused p+ ring geometries are used. This increases the breakdown of these shallowstructures. Low temperature annealing is employed to reduce the fast states on the surface.Comparisons are made between epitaxial and float zone material for the best UV response.Optimization of Si02 surface coatings are also studied. Responsivity measurements haveyielded 0.18 A/w at 380 nanometers.IntroductionThere exists a real need for highly sensitive stable devices for detecting ultra -violetradiation. This paper covers the development of high responsivity silicon photodiodesoptimized for detection around 380 nanometers. It analyzes the theoretical considerationsthat effect the UV responsivity and describes the new methods of processing that areemployed to optimize ultra -violet responsivity.There are three major effects that degrade the external responsivity of silicon from the1/A theoretical curve for a quantum detector. They are surface reflectance, surfacerecombination, and junction depth. The index of reflectance varies from 3.5 @ 1 micron to

Untuned Josephson detectors of microwave and millimeter‐wave radiation

Abstract: The intrinsic response of Josephson junctions to microwave and far‐infrared radiation is studied. Junctions are formed by pressing a Nb or Nb‐Ti pointed wire onto a Nb thin film which in turn is pressed against the open end of a waveguide. Electromagnetic radiation is applied through the back of the film so that only the wave magnetic field is coupled to the junction. The change of the dc Josephson current is monitored at different levels of microwave power over a frequency range from 22 to 105 GHz. The dependence of the responsivity of these currents on film thickness over a range from 50 to 500 A is studied. The observed responsivity agrees very well with that predicted by theory. Higher responsivity is observed for thinner films and lower microwave frequencies. The observed responsivity of a 50‐A film junction at 22 GHz is (6±3) ×10−2 V/W. To facilitate comparison of our results with other experiments, a more conventional coupling configuration in which the wave electric field rather than the wave magn...