Showing papers on "Photodiode published in 1980"

In0.53Ga0.47As photodiodes with dark current limited by generation‐recombination and tunneling

Abstract: We report on low‐dark‐current IN0.53GA0.47As photodiodes in which generation‐recombination current dominates diode leakage up to as high as 100 V. At higher voltages, tunneling currents become dominant, resulting in the soft breakdown characteristic widely observed in these materials. The dark current versus voltage characteristics have been fit to variations in current of over six orders of magnitude and a temperature range greater than 150 K using a theory which includes generation‐recombination, tunneling, and shunt components.

Self-scanned photodiode array: a multichannel spectrometric detector

Abstract: The performance characteristics of a 1024-element self-scanned photodiode array, related to its use as a multichannel spectrometric detector are described. The parameters discussed include, spectral and temporal response, blooming, geometric accuracy, noise sources, dynamic range, signal integration and spectral as well as spatial resolution.

Evidence for tunneling in reverse‐biased III‐V photodetector diodes

Abstract: Photodiodes made from III‐V group semiconductor alloys have been found to exhibit anomalously high dark currents. We present evidence that tunneling is the dominant source of dark current in many cases. The tunneling current becomes substantial at peak junction electric fields as low as 105 V/cm due to the small direct energy gaps and small effective masses of the materials tested. Tunneling sets limits on the magnitude of the electric field attainable in these materials, and therefore has serious implications on photodetector design and performance.

Ga 0.47 In 0.53 As: A ternary semiconductor for photodetector applications

Abstract: Ga 0.47 In 0.53 As has been used to make fast (rt i_{D} A) and good quantum efficiency (η Q ext > 50 percent over the entire 1.0-1.7 \mu m region of the optical spectrum). The physical properties related to the crystal growth and carrier transport are discussed in this paper in terms of both the design and the operating characteristics of detectors fabricated from this ternary alloy. The results of our work show that Ga 0.47 In 0.53 As is a material well-suited to several important semiconductor device applications. A comparison to other semiconductor photodiodes shows that Ga 0.47 In 0.53 As is one of the most sensitive detectors available in the 1.0-1.7 \mu m wavelength region. One can expect repeater-free transmission in excess of 150 km at 100 Mbits . s-1using these detectors in a digital optical fiber link at the 1.55 μm low-loss ( \alpha dB . km-1) low-dispersion transmission window.

New InGaAs/InP avalanche photodiode structure for the 1-1.6 µm wavelength region

Abstract: Low dark current and low multiplication noise properties for an In 0.53 Ga 0.47 As/InP avalanche photodiode are described. The diode is prepared with an In 0.53 Ga 0.47 As light absorption layer and an InP avalanche multiplication region. The lowest dark current density of 5.2 \times 10^{-4} A/cm2is obtained at 90 percent of a breakdown voltage. Multiplication noise power is proportional to the 2.7th power of the current multiplication factor. Impact ionization coefficient by holes is larger by 2-3 times than that by electrons in

1/f Noise in (Hg, Cd)Te photodiodes

Abstract: In this article we present results of experiments to characterize 1/ f noise in Hg 0.7 Cd 0.3 Te n+-on-p junction photodiodes. Under zero-bias voltage conditions, the photodiodes display no 1/ f noise, even in the presence of large photocurrents. Under reverse-bias voltage operation, 1/ f noise is observed. In these experiments, the 1/ f noise was measured as a function of temperature, diode bias voltage, and photon flux. Since these parameters varied the relative contributions of the various current mechanisms, the diode current mechanism responsible for 1/ f noise was isolated. It was found that 1/ f noise is independent of photocurrent and diffusion current but is linearly related to surface generation current. It is proposed that 1/ f noise in reverse-biased (Hg, Cd)Te photodiodes is a result of modulation of the surface generation current by fluctuations in the surface potential.

Tunneling Current in InGaAs and Optimum Design for InGaAs/InP Avalanche Photodiode

Abstract: Breakdown voltage and dark current density in p+n and n+p In0.53Ga0.47As diodes are compared with theoretical values taking the backward tunneling current into account. Predominant origin of dark current in an InGaAs diode is attributed to the tunneling current. Using these results, optimum design of an InGaAs/InP avalanche photodiode (APD) to obtain low dark current, high multiplication gain, high quantum efficiency and fast response is also discussed.

An integrated photoconductive detector and waveguide structure

Abstract: A new photoconductive detector is described that uses the previously reported optical field effect transistor structure The detector has good sensitivity (photoconductive gain of ∼5) and high speed (∼150 psec) Light was coupled to this detector via a 7059 glass over SiO2 waveguide The overall coupling efficiency including losses in endfire coupling was about 40%

Photodiode Array Measurement System for Implementing Abel Inversions on Emission from an Inductively Coupled Plasma

Abstract: The acquisition of detailed spatial emission data from a spectro-chemical source such as an inductively coupled plasma requires a very large number of measurements if complete information is to be obtained. A photodiode array-based measurement system has been developed for the measurement of complete spatial emission profiles of analyte lines in an inductively coupled plasma. A complete map of analyte emission throughout the plasma is acquired via the measurement of a series of horizontal emission profiles. Such horizontal emission profiles provide only lateral intensity information. These lateral intensities are converted to radial intensities by Abel inversion. The photodiode array provides an almost ideal sensor for acquisition of lateral intensity data exactly in a format for input to an Abel inversion program. The complete hardward-software system is described, and results are presented for the inductively coupled plasma.

High-speed digital lightwave communication using LEDs and PIN photodiodes at 1.3 μm

Abstract: At the wavelength of 1.3 μm, fiber loss and dispersion are sufficiently small that many lightwave communications applications can use simple and reliable LED transmitters and PIN photodiode receivers without avalanche gain. Bit rates can be as high as several hundred Mb/s. With new high-speed devices based on III–V semiconductors and microwave silicon IC technology, we have designed two fully retimed optical regenerators that operate at 1.3 μm and at bit rates of 44.7 and 274 Mb/s to study the potential of the LED-pin approach. A detailed analysis of the baseband characteristics of the LED, the fiber, and the receiver leads to an overall equalization approach that minimizes receiver noise. The success of this performance optimization is corroborated by bit-error measurements under simulated system conditions. The results suggest repeaterless operation over distances up to 24 km at 44.7 Mb/s and 8 km at 274 Mb/s for a cable loss of 1 dB/km and a bandwidth of 1000 MHz·km. The use of lasers in such multimode fiber sytems would permit larger margin allocations and penalties than those chosen for LED systems, but would not lead to substantially longer repeater spacings.

Properties of ion-implanted junctions in mercury—cadmium—telluride

Abstract: The formation of n-p junctions by ion-implantation in Hg 0.71 Cd 0.29 Te is shown to be a result of implantation damage. n-p photodiodes have been made by implantation of Ar, B, Al, and P in a p-type substrate with acceptor concentration of 4 × 1016cm-3. The implanted n-type layer is characterized by sheet electron concentration of 1014to 1015cm-2and electron mobility higher than 103cm2. V-1. s-1, for ion doses in the range 1013-5 × 1014cm-2. The photodiodes have a spectral cutoff of 5.2 µm, quantum efficiency higher than 80 percent, and differential resistance by area product above 2000 Ω . cm2at 77 K. The temperature dependence of the differential resistance is discussed. The junction capacitance dependence on reverse voltage fits a linearly graded junction model. Reverse current characteristics at 77 K have been investigated using gate-controlled diodes. The results suggest that reverse breakdown is dominated by interband tunneling in field-induced junctions at the surface, for both polarities of surface potential.

High Speed Photoresponse Mechanism of a GaAs-MESFET

Abstract: The high speed photoresponse of a GaAs-MESFET has been demonstrated using a light pulse of about 100 ps duration with a 2 GHz repetition rate generated by a GaAlAs-DH laser diode. The measured current pulse heights through the gate and through the drain as a function of the gate bias voltage confirmed a theory that the photoresponse in MESFETs is caused by the sweepout effect of photogenerated carriers in the depletion layer extending from the gate to the drain, just as in photodiodes with subsequent ordinal FET amplification.

MOS area sensor: Part II—Low-noise MOS area sensor with antiblooming photodiodes

Abstract: The development of a high-sensitivity 320 × 244 element MOS area sensor and a novel fixed pattern noise (FPN) suppressing circuit are reported in this paper. The new device incorporates p+-n+high-C photodiodes and double-diffused sense lines. The p+-n+high- C photodiodes provide a large dynamic range and a large saturation signal of 1.4 µA with 6-1x W-lamp illumination. The double-diffused sense lines are introduced to vastly improve blooming characteristics, making use of a built-in potential barrier. FPN is proved to stem mainly from inversion charge variations through horizontal switching MOS gate capacitances. A simple high-performance FPN suppressing circuit is proposed which realizes high signal-to-noise ( S/N ) ratios of more than 68 dB at saturation. The new sensor is tested in a high-sensitivity black-and-white VTR hand-held camera and will find broad applications.

Diffusion length determination in p‐n junction diodes and solar cells

Abstract: An experimental technique for determining the minority carrier diffusion length in the base region of Si p‐n junction diodes and solar cells is described. The procedure is to operate the device in the photoconductive mode and to measure its photoresponse in the wavelength region near the energy gap. The ratio of incident light intensity to photocurrent is a linear function of reciprocal absorption coefficient for each wavelength; the slope of the set of points directly yields the diffusion length. In addition, a nonlinear least‐squares analysis is also used to determine the diffusion length.

Small area ingaas/inp p-i-n photodiodes: fabrication, characteristics and performance of devices in 274 mb/s and 45 mb/s lightwave receivers at 1.31 μm wavelength

Abstract: Small-area Zn-diffused homojunction InGaAs/InP p-i-n photodetectors for wavelengths up to 1.65 μm have been fabricated in a back-illuminated configuration. The dark current is 5 nA and the capacitance is 0.3 pF at -10 V bias; the quantum efficiency is 65% without a.r. coatings. As 1.31 μm detectors in a p-i-n/f.e.t. receiver preamplifier, the diodes have provided a receiver sensitivity of -46.7 dBm at 45 Mb/s and -36 dBm at 274 Mb/s for 10-9 error rate.

InGaAs avalanche photodiode with InP p-n junction

Abstract: A new InGaAs avalanche photodiode structure that has an InGaAs light absorption region and InP avalanche multiplying region is proposed. A dark-current density of 2.2 × 10-3 A/cm2 at 90% of breakdown voltage and a multiplication factor of 45 were obtained for the new structure diode fabricated from a liquid-phase epitaxially grown wafer.

MOS area sensor: Part I—Design consideration and performance of an n-p-n structure 484 × 384 element color MOS imager

Abstract: The design consideration and performance of an n-p-n structure 484 × 384 element MOS imager is described. The imager has a photodiode array and scanners separately integrated on different p wells. The horizontal scanner, consisting of bootstrapping type noninverting circuits, features high speed and low noise. The maximum scan rate of the scanner is ∼15 MHz. The vertical scanner, consisting of inverting circuits, has a wide dynamic operating range. It can operate stably under an intense illumination of ∼ 1500 1x. Analysis of the MOS switch with a photodiode is also carried out. The 484 × 384 imager has shown excellent performances: signal to fixed-pattern-noise ratio of 54 dB, horizontal resolution of 260 TV lines, vertical resolution of 350 TV lines, well-balanced spectral response, and antiblooming.

Dual sensitivity optical sensor

Abstract: A dual sensitivity photodetector comprising a central region comprising a relatively high sensitivity reach through avalanche photo diode and a surrounding region comprising a relatively lower sensitivity P-type intrinsic N-type photodiode is disclosed which possesses the advantages of a wide sensitivity range and a relative freedom from overload.

GaAs-GaAlAs phototransistor/laser light amplifier

Abstract: A hybrid light amplifier consisting of a GaAs-GaAlAs widegap phototransistor as light detector and a d.h. laser as light emitter has been realised. Amplification up to 25 dB has been achieved. Fastest turn-on and turn-off times were 16 ns and 24 ns, respectively. A monolithically integrated amplifier structure is proposed.

GaInAsP/InP laser with monolithically integrated monitoring detector

Abstract: Monolithic fabrication of a GaInAsP/InP laser with an etched mirror and monitoring detector is reported. Stripegeometry lasers operating at wavelengths of ~1.3 ?m with threshold current of only 300 mA have been obtained. The monitoring detector on the same InP substrate was confirmed to operate with high sensitivity, comparable with that of an external Ge photodiode.

Silicon photodiode front region collection efficiency models

Abstract: The minority‐carrier transport equations are solved numerically for a realistic model of the front region of a UV‐enhanced silicon photodiode. Surface recombination is shown to be the dominant quantum efficiency reducing mechanism. Auger recombination is shown to be almost negligible for the type of diode under investigation.

Very high quantum efficiency GaSb mesa photodetectors between 1.3 and 1.6 μm

Abstract: In this letter very high quantum efficiency GaSb mesa photodiodes with AlxGa1−xSb windows are reported for the first time External quantum efficiencies (ηext) of ≃60% at zero bias and of ≃70% at −1 V near 13 μm have been obtained without antireflection coatings More than 80% of the devices from several wafers exhibited ηext⩾50% at λ≃13 μm

Dark current and breakdown characteristics of dislocation‐free InP photodiodes

Abstract: The reverse I‐V characteristics of InP p‐n junction mesa photodiodes carefully fabricated to contain only a small number of dislocation etch pits were studied and compared. The results show that I varies with V approximately as expected for defect‐free junctions only when the mesas contain no visible etch pits.

Electro-optic devices

Abstract: An electro-optic device for stabilizing the output level of a Burrus-type light emitting diode (LED) utilizes a photodiode to monitor side emission from an active region of the LED. Side emission closely tracks top emission, which is launched into an output fiber. An electrical analog is derived from the monitored side emission and is applied in a feedback loop to control modulation level or bias current to the LED. In this way, peak optical output (for digital systems) or r.m.s. output and linearity (for analog systems) is stabilized. The monitoring photodiode and the LED may be spatially separate or may form a unitary structure.

p-i-n/f.e.t. hybrid optical receiver for longer-wavelength optical communication systems

Abstract: Preliminary results are reported on the first GaInAs p-i-n/f.e.t. hybrid optical receiver for longer-wavelength optical communication systems. The GaInAs photodiode has a capacitance of 0.3 pF and quantum efficiency of 25%, and gives a receiver sensitivity for a 140 Mbit/s n.r.z. system at 1.24 μm of −40.7 dBm for a 10−9 error rate.

Method of coupling between an optical fiber and an optoelectronic diode, and a transmitting or receiving head fabricated by means of said method

Abstract: A method of optical coupling between an optical fiber and an optoelectronic component for an optical-fiber telecommunications link is applied to the fabrication of a transmitting and/or receiving optoelectronic head. In a semiconductor wafer having a p - layer and a p + layer, chemical etching of the p - layer is followed by n-type doping of an n + layer at the bottom of the cavity and on the edge of the cavity. Highly accurate positioning of the optical fiber is thus ensured as well as excellent coupling between the fiber and the light-emitting diode or photodiode thus provided.

Picosecond optical sampling technique for measuring the speed of fast electro‐optic switch/modulators

Abstract: We propose and demonstrate a new technique for measuring the pulse response of fast electro‐optic switch/modulators. Using synchronized trains of electrical drive pulses and picosecond optical sampling pulses, switching times as short as ∼50 psec can be measured without requiring a fast photodiode.

Light intensity modulator in an integrated optical circuit with feedback means

Abstract: The invention relates to a light intensity modulator, in integrated optics and an integrated optical circuit comprising such a modulator. The modulator comprises a two-arm interferometer in which there is created by electro-optical effect, a phase shift controlled by a modulating voltage between the light waves propagated in the two arms. It is characterized by a feedback loop comprising a light separator placed on the output guide of the interferometer, and a photodiode collecting the fraction of output intensity from the separator and supplying an electric voltage which is superimposed in the interferometer on the modulating voltage. Thus linearization of the output intensity-modulating voltage response curve is obtained.