Characteristics Of Photodiodes Research Articles

Vacuum ultraviolet ellipsometer using inclined detector as analyzer to measure stokes parameters and optical constants — With results for AlN optical constants

Principle and analysis for ellipsometers usable in the vacuum ultraviolet (VUV) region up to about 25eV, which are consisting of a sample mirror and an inclined photodiode, are described. Our ellipsometer has two degrees of freedom in rotation; the main chamber can rotate around the axis of incidence and, the analyzer unit can also rotate around the axis of reflection. All the unknown parameters (Stokes parameters of the source, ellipsometric parameters of the sample and the polarization sensitivity of the inclined detector) are obtained by rotating the main chamber and analyzer independently and solving the simultaneous equations with the measurands. Measurement results on polarization characteristics of photodiodes, Stokes parameters of the beam emerging from a synchrotron radiation beamline, and optical constants of AlN film are given. It is concluded that the ellipsometer is advantageous in the simplicity and worked as intended.

Characterization of n-Ge/i-Ge/p-Si PIN photo-diode

A PIN photo-diode was fabricated from the phosphorus doped n-Ge/i-Ge/p-Si hetero-structure grown by rapid thermal chemical vapor deposition (RTCVD). The surface morphology of the n-Ge/i-Ge layer was found to be mirror like and the n-Ge/i-Ge layer was under a tensile strain of ~0.071%. The phosphorus doping concentration and the RMS surface roughness were 2×1019cm−3 and 2.46nm, respectively. Current–voltage characteristics of the PIN photo-diode showed a forward saturation current density of 0.63A/cm2 at 2V and reverse-biased characteristics behaved similar to forward-biased characteristics of the diode. Roll-off in spectral response was observed at wavelengths greater than 1600nm which could be attributed to decreased absorption of Ge at room temperature.

3-λ characterization of phase response for optical receivers

We propose a novel digital signal processing (DSP) algorithm for photodiode characterization probed by three wavelengths. The DSP algorithm has low computational complexity. The required number of measurements increases logarithmically with the number of spectral points. For the first time to our knowledge, the phase response of photodiode is characterized up to 20 GHz.

A Theoretical and Experimental Determination of the Internal Quantum Efficiency of Silicon Photodiodes

A new method of processing the experimental current-voltage characteristics of photodiodes using reference points is proposed. By comparing a trap detector, developed at the All-Russia Research Institute of Optophysical Measurements based on Hamamatsu S6337 photodiodes with an HH-03-1337 trap detector, certified using a cryogenic radiometer at the PTB, an experimental value of the internal quantum efficiency of the Hamamatsu S6337 photodiode is obtained.

Primary ultrasonic interferometer photodiode characterization using frequency-modulated laser wavefront radiation

Photodiodes play an important role in many optical systems and, as such, their stability and performance are of great importance. Manufacturers of such detectors typically only provide information regarding their sensitivity as a function of the optical wavelength and this is often sufficient for applications such as telecommunications. However, in certain applications such as primary ultrasonic standards based on interferometry, the frequency response of the photodiodes is of critical importance because, for accurate calibration, a correction factor must be applied, which contributes a major source of measurement uncertainty. Most optical calibration systems reported in the literature operate either in the GHz range or a very limited MHz range. This work reports on the development of a system based on rotational optical components that produces light patterns scanned through a slit at varying speeds using different deflection mechanisms. This results in the generation of spatially dependent interference fringes in the range 1 Hz up to 115 MHz with an expanded uncertainty of less than 5% for the majority of its frequency range of operation.

Investigations on an Ultra-Thin Bendable Monolithic Si CMOS Image Sensor

In this paper, theoretical as well as experimental results of the investigations on a bendable ultrathin Si monolithic CMOS image sensor are presented. The electro-optical behavior of a thinned flexible CMOS active pixel sensor for the application of uniaxial mechanical stress is theoretically and experimentally analyzed. The necessity of a correlated double sampling readout scheme to achieve a stress-independent operation is underlined. Optical as well as electrical characteristics of standard photodiodes on ultrathin silicon chips embedded into a polyimide foil under several bending configurations are discussed and experimental data are presented. Moreover, design rules for the stress-independent operation of a flexible ultrathin image sensor are given and the thinning and the encapsulation processes are shortly presented.

Fabrication of PIN photo-diode from p-Ge/i-Ge/n-Si hetero junction structure

A pin photo-diode was fabricated from the p-Ge/i-Ge/n-Si hetero junction structure grown by using rapid thermal chemical vapor deposition (RTCVD). The structural properties of the p-Ge/i-Ge/n-Si hetero junction structure were investigated using high-resolution X-ray diffraction (HRXRD). Specifically, the recent advances in the dry etching of p-Ge/i-Ge/n-Si hetero junction structure have been used to define pin photo-diode p-Ge/i-Ge layer mesas. I–V characteristics of the pin photo-diode indicate a reasonable reverse saturation current of 96μA at −1V and a high reverse breakdown voltage in excess of −100V. The photocurrent with a responsivity of 0.19A/W at the wavelength of 1.55μm is flat over a wide range of reverse bias voltage and the leakage currents is 700nA at a reverse 0.1V bias voltage. The roll-off in photocurrent spectra after wavelength of 1600nm is expected due to the decreased absorption of Ge at room temperature.

Optically Powered Voltage Supply Device for Effective Utilization of Optical Energy in the Fiber‐to‐the‐Home Network

SUMMARYAn optically powered device using an InGaAs photodiode has been developed. This study aims to harvest light energy (2.8 to 500 μW) from the FTTH (fiber‐to‐the‐Home) network and to utilize it for operating remote sensors without an external energy source. We designed the booster circuit and evaluated its characteristics, confirming that it could boost an input voltage of 0.3 V to 3.0 V. We also evaluated the characteristics of an InGaAs photodiode and confirmed that it could output a voltage over 0.3 V using 10‐μW input light. We demonstrate that a ready‐made sensor can be operated with an input optical power as low as 10 μW. © 2013 Wiley Periodicals, Inc. Electron Comm Jpn, 96(10): 37–42, 2013; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/ecj.11472

Cooled photodiodes based on a type-II single p-InAsSbP/n-InAs heterostructure

Analysis of current-voltage and spectral characteristics of photodiodes based on a single p-InAsSbP/n-InAs heterostructure formed on a heavily doped n +-InAs substrate (n + ∼ 1018 cm−3) is presented. It is shown that, at low temperatures (77 < T < 190 K), the generation-recombination current flow mechanism typical of p-i-n diodes dominates. Expected parameters of the photodiode that can be obtained using these heterostructures are presented.

Ultraviolet photodiodes based on AlGaN solid solutions

We present the characteristics of ultraviolet photodiodes based on Schottky barriers to the Aluminum Gallium Nitride (AlGaN) solid solution. The paper is devoted to the creation of ohmic and rectifying contacts to AlxGa1−xN solid solutions with a high (x > 0.5) proportion of AlN. The most important property of (AlxGa1−xN) materials is their solar blindness: the wide bandgap (Eg = 3.4 eV for GaN; 6.2 eV for AlN) makes these materials insensitive to the visual and IR light. The study of solid solutions with various mole fractions of Al has created solar-blind and see-blind ultraviolet photodetectors.

Long Wavelength Infrared Superlattice Detectors and FPAs Based on CBIRD Design

In this letter, we demonstrate the next generation of N+-p complementary barrier infrared detectors (nCBIRD) with 9.9 μm cutoff wavelength that have near zero bias operation and exhibit dark current density of 6 × 10-6 A/cm2 at 77 K. These nCBIRDs have been recently utilized in the 320 × 256 focal plane array that exhibited a noise equivalent differential temperature of 18.6 mK at an operating temperature of 77 K, with a 300 K background and f/2 cold-stop. We compare single pixel photodiode characteristics with the performance of FPAs that were fabricated together on the same wafer. This letter identifies the physical processes affecting the performance of long wave infrared photodetectors based on CBIRD design.

Characteristics of nanostructured CdO/Si heterojunction photodetector synthesized by CBD

In the present work, CdO/Si heterojunction detectors were fabricated by depositing nanostructured CdO film on single crystal silicon wafer by chemical bath deposition (CBD) technique. Films deposition was carried out at different temperatures. To obtain good film stoichiometry heating of films in static air at temperature of 400°C for 90min was carried out. The structural properties of CdO films was characterized by X-ray diffraction and atomic force microscope (AFM), these investigations showed that the deposited CdO films have cubic structure. The surface morphology investigation revealed that CdO film is almost homogeneous and consisted of the nanowires with diameter less than 100nm at temperature of solution 40°C.The band gap of the films changes from 2.4 to 2.5eV with increasing preparation temperature. The current–voltage characteristics of photodiodes under dark exhibit good rectification behavior and that ideality factor of heterojunction was found to be in the range of 1.56–3.69 depending on solution temperature. The capacitance–voltage characteristic shows a typical abrupt heterojunction and the built-in-potential was determined. CdO/Si detector has good spectral responsivity in visible and NIR and the maximum responsivity was 0.56A/W. Rise time of the photodetectors was strongly dependent on solution temperature and the shortest rise time obtained was 45ns at 2V.

Silicon-on-insulator spectrometers with integrated GaInAsSb photodiodes for wide-band spectroscopy from 1510 to 2300 nm

We present a silicon-on-insulator (SOI) based spectrometer platform for a wide operational wavelength range. Both planar concave grating (PCG, also known as echelle grating) and arrayed waveguide grating (AWG) spectrometer designs are explored for operation in the short-wave infrared. In addition, a total of four planar concave gratings are designed to cover parts of the wavelength range from 1510 to 2300 nm. These passive wavelength demultiplexers are combined with GaInAsSb photodiodes. These photodiodes are heterogeneously integrated on SOI with benzocyclobutene (DVS-BCB) as an adhesive bonding layer. The uniformity of the photodiode characteristics and high processing yield, indicate a robust fabrication process. We demonstrate good performance of the miniature spectrometers over all operational wavelengths which paves the way to on-chip absorption spectroscopy in this wavelength range.

Improvement possibilities of the I-V characteristics of PIN photodiodes damaged by gamma irradiation

This paper presents the behavior of PIN photodiodes after combined gamma and neutron irradiation. Different types of PIN photodiodes have been exposed first to gamma and then to neutron irradiation. I-V characteristics (current dependence on voltage) of photodiodes have been measured after each of these irradiations. It has been noted that the photocurrent level after the neutron irradiation is higher than before it, which is not consistent with the current theories about the effects of neutron radiation on semiconductors. In order to explain this behavior of the photodiodes, the Monte Carlo simulation of photon transport through the material has been used. It is proposed that a possible cause for current enhancement are defects in semiconductor created by gamma irradiation and effects of neutron irradiation on these defects. The results can be explained by an intercentre transfer of charge between defects in close proximity to each other. The aim of this paper is to investigate the improvement possibilities of the I-V characteristics of PIN photodiodes, and photodetectors in general, damaged by gamma irradiation.

Damage Induced by Neutron Radiation on Output Characteristics of Solar Cells, Photodiodes, and Phototransistors

This study investigates the effects of neutron radiation onI-Vcharacteristics (current dependance on voltage) of commercial optoelectronic devices (silicon photodiodes, phototransistors, and solar panels). Current-voltage characteristics of the samples were measured at room temperature before and after irradiation. The diodes were irradiated using Am-Be neutron source with neutron emission of2.7×106 n/s. The results showed a decrease in photocurrent for all samples which could be due to the existence of neutron-induced displacement defects introduced into the semiconductor lattice. The process of annealing has also been observed. A comparative analysis of measurement results has been performed in order to determine the reliability of optoelectronic devices in radiation environments.

Improved electrical characteristics of porous germanium photodiode obtained by phosphorus ion implantation

Germanium–based photodetectors are the standard technology used for radiometric measurement in the IR spectral range. Shallow PN+ junctions were obtained by using ion implantation in p–type germanium. N–type doping was achieved by phosphorus implantation at a dose of 1 × 1015 cm−2 doses and an energy of 150 keV followed by annealing at 600°C for 2 h. In order for the new detector to be used as a standard for radiometric measurement, a porous layer is introduced on the active surface. After metallisation by thermal evaporation of indium (In) on the front side and gold (Au) on the back side, the new porous germanium–based photodetector is essentially done. The electrical behaviour of this porous germanium photodiode is characterised by current–voltage measurements that are compared to the I–V characteristic of classical germanium photodiodes. The results of this study show a huge increase of the photocurrent, a significant increase of the shunt resistance and low series resistance. Effects of low shunt resistance are also discussed. AFM showed that the porous layer contributes to trap the incident optical radiation and to reduce the reflection coefficient fluctuations of the front face of the photodiode.

Characteristics of Nanostructure Silicon Photodiode using Laser Assisted Etching

Abstract We prepared nanostructures silicon photodiode (nPSi) by using laser assisted etching at fixed current density (30 mA/cm2) with different etching wavelengths of laser diode (532,650 and 810 nm), a (metal/nanostructure silicon/metal) photodiode has been fabricated from rapid thermal oxidation (RTO) and rapid thermal annealing (RTA) processes to improve the characterizations of PSi photodiode, A responsivity of (3A/w) was measured at (450 nm) with low value of dark current (1.33 μA/ cm) and higher value of photo current (610 μA/cm 2 ) at 5 volt reverse bias. The results show that the wavelength IR (810 nm) give us the best photodiode and electrical characteristics.

P-N Junction of NiO Thin Film for Photonic Devices

The development of a short-wavelength p-n junction device is essentially important for the realization of transparent electronics for next-generation optoelectronics. Nickel oxide (NiO) thin films with a tunable electrical conductivity of both p-type and n-type under the optimized growth conditions using RF sputtering technique with high optical transmission in the visible region have been fabricated. The room-temperature conductivities for n-type and p-type NiO thin films were about 5.91 × 101 and 1.9 ×10-2 S·cm-1, respectively. A p-n junction of NiO thin film has been realized, successfully exhibiting good rectifying behavior with efficient UV photodiode characteristics, providing suitable solution for low-cost visible blind UV photodetector application.

Fabrication and characteristics of photodiode based on ZnO nanowire arrays and spray-coated regioregular P3HT layers

A photodiode based on well-aligned ZnO nanowire arrays (ZNAs) and spray-coated regioregular poly(3-hexylthiophene-2,5-diyl) (P3HT) layers hybrid hetero junctions was fabricated, and its electrical characteristics in dark and under illumination with a solar simulator were investigated. Current–voltage (I–V) data of ITO/ZNAs/P3HT/Ag device in dark and under illumination showed typical diode characteristics. A rectification ratio (RR) of 22.7 at 1.7V and a low turn-on voltage of 0.4V in dark were obtained. Also, the photodiode with high photo-response in the order of 0.31A/W at -2V using 80mW/cm2 illumination power was observed. Upon increasing illumination power from 40 to 100mW/cm2, the RR value for the photodiode continuously was improved with a highest value of 12.5.

Parameter determination from current–voltage characteristics of HgCdTe photodiodes in forward bias region

Current–voltage characteristics of HgCdTe photodiodes in the forward bias region have been modeled considering mechanisms including drift-diffusion current, recombination current, metal-semiconductor contact and constant series resistance. Moreover, a fitting method based on the genetic algorithm has been developed to obtain values of related physical parameters from the measured dynamic resistance–voltage curves. Fitting results of \(n^+\)-on-\(p\) planar devices with different cutoff wavelengths are presented to illustrate the model and method, which are available and promising in acquiring device parameter values and evaluating the electrode contact quality.