scholarly journals Higher Operating Temperature IR Detectors of the MOCVD Grown HgCdTe Heterostructures

2020 ◽  
Vol 49 (11) ◽  
pp. 6908-6917
Author(s):  
P. Madejczyk ◽  
W. Gawron ◽  
A. Kębłowski ◽  
K. Mlynarczyk ◽  
D. Stępień ◽  
...  
Keyword(s):  
Infrared Detectors ◽  
Diffusion Processes ◽  
Operating Temperature ◽  
Chemical Vapour ◽  
Dual Band ◽  
Theoretical Modelling ◽  
Organic Chemical ◽  
Ir Detectors ◽  
Wide Range ◽  
Technology Improvement

Abstract This paper summarizes progress in metal organic chemical vapour deposition (MOCVD) technology achieved in recent years at the Institute of Applied Physics, Military University of Technology and VIGO System S.A. MOCVD with a wide range of composition and donor/acceptor doping and without post-growth annealing is a very convenient tool for the deposition of HgCdTe epilayers used for uncooled infrared detectors. Particular attention is focused on: surface morphology improvement, doping issues, diffusion processes during growth study, substrate issues, crystallographic orientation selection. In this respect, MOCVD technology improvement influencing IR detector parameters is shown. CdTe buffer layer deposition allows HgCdTe heterostructure growth on GaAs substrates. Theoretical modelling using APSYS platform supports designing and better understanding of the carrier transport mechanism in detector’s structures. Secondary ion mass spectrometry profiles allows to compare projected and obtained structures and revealed diffusion processes of the elements. A wide range of different types of infrared detectors operating at high operating temperature conditions has been constructed: photoresistors, non-equilibrium photodiodes, dual-band photodiodes, barrier and multiple detectors. The methodical research efforts contributed to the time constant reduction are important in many detector applications. Future challenges and prospects are also discussed.

scholarly journals MOCVD Grown HgCdTe Heterostructures for Medium Wave Infrared Detectors

Coatings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 611
Author(s):  
Waldemar Gawron ◽  
Jan Sobieski ◽  
Tetiana Manyk ◽  
Małgorzata Kopytko ◽  
Paweł Madejczyk ◽  
...  
Keyword(s):  
Buffer Layer ◽  
Infrared Detectors ◽  
Lattice Mismatch ◽  
Layer Growth ◽  
Ex Situ ◽  
Current Status ◽  
Organic Chemical ◽  
Infrared Band ◽  
Donor And Acceptor ◽  
Wide Range

This paper presents the current status of medium-wave infrared (MWIR) detectors at the Military University of Technology’s Institute of Applied Physics and VIGO System S.A. The metal–organic chemical vapor deposition (MOCVD) technique is a very convenient tool for the deposition of HgCdTe epilayers, with a wide range of compositions, used for uncooled infrared detectors. Good compositional and thickness uniformity was achieved on epilayers grown on 2-in-diameter, low-cost (100) GaAs wafers. Most growth was performed on substrates, which were misoriented from (100) by between 2° and 4° in order to minimize growth defects. The large lattice mismatch between GaAs and HgCdTe required the usage of a CdTe buffer layer. The CdTe (111) B buffer layer growth was enforced by suitable nucleation procedure, based on (100) GaAs substrate annealing in a Te-rich atmosphere prior to the buffer deposition. Secondary-ion mass spectrometry (SIMS) showed that ethyl iodide (EI) and tris(dimethylamino)arsenic (TDMAAs) were stable donor and acceptor dopants, respectively. Fully doped (111) HgCdTe heterostructures were grown in order to investigate the devices’ performance in the 3–5 µm infrared band. The uniqueness of the presented technology manifests in a lack of the necessity of time-consuming and troublesome ex situ annealing.

Zeolates: A Coordination Chemistry View of Metal-Ligand Bonding in Intrazeolite MOCVD Type Precursors and Semiconductor Nanoclusters

1992 ◽  
Vol 277 ◽  
Author(s):  
Geoffrey A. Ozin ◽  
Carol L. Bowes ◽  
Mark R. Steele
Keyword(s):  
Self Assembly ◽  
Materials Science ◽  
Zeolite Y ◽  
Chemical Vapour ◽  
Internal Surface ◽  
Building Blocks ◽  
Structural Features ◽  
Organic Chemical ◽  
Wide Range ◽  
Shape Selective

ABSTRACTVarious MOCVD (metal-organic chemical vapour deposition) type precursors and their self-assembled semiconductor nanocluster products [1] have been investigated in zeolite Y hosts. From analysis of in situ observations (FTIR, UV-vis reflectance, Mössbauer, MAS-NMR) of the reaction sequences and structural features of the precursors and products (EXAFS and Rietveld refinement of powder XRD data) the zeolite is viewed as providing a macrospheroidal, multidendate coordination environment towards encapsulated guests. By thinking about the α- and β-cages of the zeolite Y host effectively as a zeolate ligand composed of interconnected aluminosilicate “crown ether-like” building blocks, the materials chemist is able to better understand and exploit the reactivity and coordination properties of the zeolite internal surface for the anchoring and self-assembly of a wide range of encapsulated guests. This approach helps with the design of synthetic strategies for creating novel guest-host inclusion compounds having possible applications in areas of materials science such as nonlinear optics, quantum electronics, and size/shape selective catalysis.

1.55 Micron Emission from InAs/InP Self-Assembled Quantum Dots

1999 ◽  
Vol 571 ◽  
Author(s):  
Ray Murray ◽  
Caroline Bryan ◽  
Chris Button ◽  
D. Spikes ◽  
G. Hill
Keyword(s):  
Quantum Dots ◽  
Quantum Well ◽  
Room Temperature ◽  
Chemical Vapour ◽  
Organic Chemical ◽  
Wide Range ◽  
Metal Organic ◽  
Self Assembled ◽  
Multi Quantum Well

ABSTRACTSelf-assembled InAs/InP and InAs/InGaAsP quantum dots (QDs) grown by metal-organic chemical vapour epitaxy (MOVPE) exhibit emission at 1.5–1.6 μm at room temperature. P-I-N diodes incorporating a single InAs/InGaAsP QD layer exhibit strong electroluminescence over a wide range of input currents and emit significantly more light per layer than a InGaAs/InGaAsP multi-quantum well device.

High-operating temperature MWIR nBn HgCdTe detector grown by MOCVD

2013 ◽  
Vol 21 (4) ◽  
Author(s):  
M. Kopytko ◽  
A. Kębłowski ◽  
W. Gawron ◽  
P. Madejczyk ◽  
A. Kowalewski ◽  
...  
Keyword(s):  
Operating Temperature ◽  
Chemical Vapor ◽  
Organic Chemical ◽  
Wide Range ◽  
Donor Acceptor ◽  
Metal Organic ◽  
Barrier Detectors ◽  
Barrier Device ◽  
Organic Chemical Vapor Deposition ◽  
Iodine Diffusion

AbstractThe paper reports on the first experimental results of the mid-wave infrared (MWIR) HgCdTe barrier detectors operated at near-room temperatures and fabricated using metal organic chemical vapor deposition (MOCVD). SIMS profiles let to compare projected and obtained structures and reveals interdiffusion processes between the layers. Undesirable iodine diffusion from cap to the barrier increase the valance band offset and is the key item in limiting the performance of HgCdTe nBn detector. However, MOCVD technology with a wide range of composition and donor/acceptor doping and without post grown annealing might be successfully adopted for barrier device architectures.

Electron microscope characterization of MOCVD-grown gap layers on Si

1986 ◽  
Vol 44 ◽  
pp. 724-725
Author(s):  
K.M. Jones ◽  
M.M. Al-Jassim ◽  
J.M. Olson
Keyword(s):  
Atmospheric Pressure ◽  
Vapour Deposition ◽  
Chemical Vapour ◽  
Organic Chemical ◽  
Lattice Match ◽  
Si Substrates ◽  
Metal Organic ◽  
Good Lattice ◽  
Antiphase Domains

The epitaxial growth of III-V semiconductors on Si for integrated optoelectronic applications is currently of great interest. GaP, with a lattice constant close to that of Si, is an attractive buffer between Si and, for example, GaAsP. In spite of the good lattice match, the growth of device quality GaP on Si is not without difficulty. The formation of antiphase domains, the difficulty in cleaning the Si substrates prior to growth, and the poor layer morphology are some of the problems encountered. In this work, the structural perfection of GaP layers was investigated as a function of several process variables including growth rate and temperature, and Si substrate orientation. The GaP layers were grown in an atmospheric pressure metal organic chemical vapour deposition (MOCVD) system using trimethylgallium and phosphine in H2. The Si substrates orientations used were (100), 2° off (100) towards (110), (111) and (211).

Structural and electronic properties of defects in semiconductors

1995 ◽  
Vol 53 ◽  
pp. 4-5
Author(s):  
J.L. Batstone
Keyword(s):  
Semiconductor Device ◽  
Chemical Vapor ◽  
Misfit Strain ◽  
Organic Chemical ◽  
Extended Defects ◽  
Transmission Electron ◽  
Semiconductor Thin Films ◽  
Wide Range ◽  
Metal Organic ◽  
Film Substrate

The development of growth techniques such as metal organic chemical vapor deposition (MOCVD) and molecular beam epitaxy during the last fifteen years has resulted in the growth of high quality epitaxial semiconductor thin films for the semiconductor device industry. The III-V and II-VI semiconductors exhibit a wide range of fundamental band gap energies, enabling the fabrication of sophisticated optoelectronic devices such as lasers and electroluminescent displays. However, the radiative efficiency of such devices is strongly affected by the presence of optically and electrically active defects within the epitaxial layer; thus an understanding of factors influencing the defect densities is required.Extended defects such as dislocations, twins, stacking faults and grain boundaries can occur during epitaxial growth to relieve the misfit strain that builds up. Such defects can nucleate either at surfaces or thin film/substrate interfaces and the growth and nucleation events can be determined by in situ transmission electron microscopy (TEM).

Characterisation of multilayer materials using a position-sensitive atom probe

1990 ◽  
Vol 48 (4) ◽  
pp. 624-625
Author(s):  
RAD Mackenzie ◽  
G D W Smith ◽  
A. Cerezo ◽  
J A Liddle ◽  
CRM Grovenor ◽  
...  
Keyword(s):  
Quantum Well ◽  
Quantum Wells ◽  
Spatial Information ◽  
Chemical Vapour ◽  
Atom Probe ◽  
Organic Chemical ◽  
Growth Stages ◽  
Multiple Quantum ◽  
Quartz Wool ◽  
Position Sensitive

The position sensitive atom probe (POSAP), described briefly elsewhere in these proceedings, permits both chemical and spatial information in three dimensions to be recorded from a small volume of material. This technique is particularly applicable to situations where there are fine scale variations in composition present in the material under investigation. We report the application of the POSAP to the characterisation of semiconductor multiple quantum wells and metallic multilayers.The application of devices prepared from quantum well materials depends on the ability to accurately control both the quantum well composition and the quality of the interfaces between the well and barrier layers. A series of metal organic chemical vapour deposition (MOCVD) grown GaInAs-InP quantum wells were examined after being prepared under three different growth conditions. These samples were observed using the POSAP in order to study both the composition of the wells and the interface morphology. The first set of wells examined were prepared in a conventional reactor to which a quartz wool baffle had been added to promote gas intermixing. The effect of this was to hold a volume of gas within the chamber between growth stages, leading to a structure where the wells had a composition of GalnAsP lattice matched to the InP barriers, and where the interfaces were very indistinct. A POSAP image showing a well in this sample is shown in figure 1. The second set of wells were grown in the same reactor but with the quartz wool baffle removed. This set of wells were much better defined, as can be seen in figure 2, and the wells were much closer to the intended composition, but still with measurable levels of phosphorus. The final set of wells examined were prepared in a reactor where the design had the effect of minimizing the recirculating volume of gas. In this case there was again further improvement in the well quality. It also appears that the left hand side of the well in figure 2 is more abrupt than the right hand side, indicating that the switchover at this interface from barrier to well growth is more abrupt than the switchover at the other interface.

Reduction of carbon impurities in aluminium nitride from time-resolved chemical vapour deposition using trimethylaluminum

2020 ◽  
Author(s):  
Polla Rouf ◽  
Pitsiri Sukkaew ◽  
Lars Ojamäe ◽  
Henrik Pedersen
Keyword(s):  
Chemical Vapour Deposition ◽  
Vapour Deposition ◽  
Chemical Vapour ◽  
Aluminium Nitride ◽  
Methyl Groups ◽  
Time Resolved ◽  
Thermally Induced ◽  
Light Emitting ◽  
Carbon Impurities ◽  
Wide Range

<p>Aluminium nitride (AlN) is a semiconductor with a wide range of applications from light emitting diodes to high frequency transistors. Electronic grade AlN is routinely deposited at 1000 °C by chemical vapour deposition (CVD) using trimethylaluminium (TMA) and NH<sub>3</sub> while low temperature CVD routes to high quality AlN are scarce and suffer from high levels of carbon impurities in the film. We report on an ALD-like CVD approach with time-resolved precursor supply where thermally induced desorption of methyl groups from the AlN surface is enhanced by the addition of an extra pulse, H<sub>2</sub>, N<sub>2</sub> or Ar between the TMA and NH<sub>3</sub> pulses. The enhanced desorption allowed deposition of AlN films with carbon content of 1 at. % at 480 °C. Kinetic- and quantum chemical modelling suggest that the extra pulse between TMA and NH<sub>3</sub> prevents re-adsorption of desorbing methyl groups terminating the AlN surface after the TMA pulse. </p>

VLSI DESIGN OF PIPELINED ADC WITH WIDE RANGE OPERATING TEMPERATURE FOR WAVE APPLICATIONS

2017 ◽  
Vol 6 (2) ◽  
pp. 13
Author(s):  
P LOKESH ◽  
U. SOMALATHA ◽  
S. CHANDANA ◽  
◽  
◽  
...  
Keyword(s):  
Operating Temperature ◽  
Vlsi Design ◽  
Pipelined Adc ◽  
Wide Range

Semiconductors

2018 ◽  
Author(s):  
L. Solymar ◽  
D. Walsh ◽  
R. R. A. Syms
Keyword(s):  
Crystal Growth ◽  
Molecular Beam ◽  
Vapour Deposition ◽  
Energy Levels ◽  
Chemical Vapour ◽  
Optical Excitation ◽  
Organic Chemical ◽  
Metal Organic ◽  
Mathematical Relations ◽  
Semiconductor Properties

Both intrinsic and extrinsic semiconductors are discussed in terms of their band structure. The acceptor and donor energy levels are introduced. Scattering is discussed, from which the conductivity of semiconductors is derived. Some mathematical relations between electron and hole densities are derived. The mobilities of III–V and II–VI compounds and their dependence on impurity concentrations are discussed. Band structures of real and idealized semiconductors are contrasted. Measurements of semiconductor properties are reviewed. Various possibilities for optical excitation of electrons are discussed. The technology of crystal growth and purification are reviewed, in particular, molecular beam epitaxy and metal-organic chemical vapour deposition.

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