Oxygen Doping of GaAs During Omvpe Controlled Introduction of Impurity Complexes

1993 ◽  
Vol 325 ◽  
Author(s):  
Y. Park ◽  
M. Skowronski ◽  
T.S. Rosseel ◽  
M.O. Manasreh
Keyword(s):  
Low Temperature ◽  
Deep Level ◽  
Growth Conditions ◽  
Near Band Edge ◽  
Second Phase ◽  
Temperature Growth ◽  
Temperature Deposition ◽  
Localized Vibrational Modes ◽  
Secondary Ion ◽  
Reactor Pressure

AbstractGaAs epilayers have been grown by Organo-Metallic Vapor Phase Epitaxy using dimethylaluminum methoxide as a dopant source. This compound contains a strong aluminumoxygen bond which is thought to remain intact during low temperature deposition and result in the incorporation of Al-O as a complex. Incorporation of aluminum and oxygen was investigated by Secondary Ion Mass Spectroscopy as a function of growth conditions: growth temperature, growth rate, V/III ratio, reactor pressure and dopant mole fraction. High doping levels up to 1020 cm−3 (for both oxygen and aluminum) were achieved without degradation of surface morphology andlor precipitation of a second phase. Oxygen concentration is lower than that of aluminum for all investigated growth conditions but at low deposition temperatures oxygen/aluminum ratios approach 1, indicating that Al-O is incorporated as a pair. Infrared absorption measurements in the 600-1200 cm−1 range did not detect well known isolated oxygen localized vibrational modes (LVM). Also in layers grown at low temperatures the intensity of isolated aluminum LVM at 362 cm−1 is much smaller than the concentration obtained by SIMS. Both observations prove that oxygen not only is incorporated as an Al-O pair but remains bonded in the bulk of the layer. Low temperature photoluminescence measurements indicate that the A1-O complex is electrically active in GaAs, forms a deep level within the GaAs band gap, and serves as an efficient non-radiative recombination center. Near band edge luminescence intensity correlates well incorporation of oxygen. The Al-O pairs act as deep acceptors in GaAs and cause the compensation of shallow tellurium donors.

Low-temperature growth conditions of YBa2Cu3O7−δ using Ba–Cu–Ag–O–F solvent

2002 ◽  
Vol 236 (1-3) ◽  
pp. 221-224 ◽  
Author(s):  
Yasuji Yamada ◽  
Toshihiro Suga ◽  
Izumi Hirabayashi
Keyword(s):  
Low Temperature ◽  
Growth Conditions ◽  
Temperature Growth ◽  
Low Temperature Growth

Influence of n-Type Doping Levels on Carrier Lifetime in 4H-SiC Epitaxial Layers

2017 ◽  
Vol 897 ◽  
pp. 238-241 ◽  
Author(s):  
Louise Lilja ◽  
Ildiko Farkas ◽  
Ian Booker ◽  
Jawad ul Hassan ◽  
Erik Janzén ◽  
...  
Keyword(s):  
Low Temperature ◽  
Deep Level Transient Spectroscopy ◽  
Doping Level ◽  
Carrier Lifetime ◽  
Deep Level ◽  
Growth Conditions ◽  
Epitaxial Layers ◽  
Drastic Decrease ◽  
Transient Spectroscopy ◽  
Low Temperature Photoluminescence

In this study we have grown thick 4H-SiC epitaxial layers with different n-type doping levels in the range 1E15 cm-3 to mid 1E18 cm-3, in order to investigate the influence on carrier lifetime. The epilayers were grown with identical growth conditions except the doping level on comparable substrates, in order to minimize the influence of other parameters than the n-type doping level. We have found a drastic decrease in carrier lifetime with increasing n-type doping level. Epilayers were further characterized with low temperature photoluminescence and deep level transient spectroscopy.

Dependence on MOCVD Growth Temperature of The Photoluminescence Properties of ZnSe, ZnTe, and ZnSe(1-x)Te(x) Alloys and ZnSe/ZnTe Superlattices

1992 ◽  
Vol 263 ◽  
Author(s):  
B.E. Ponga ◽  
J. Calas ◽  
M. Averous ◽  
T. Cloitre ◽  
O. Briot ◽  
...  
Keyword(s):  
Low Temperature ◽  
Chemical Vapor ◽  
Growth Conditions ◽  
Organic Chemical ◽  
Physical Situation ◽  
Temperature Growth ◽  
Mocvd Growth ◽  
Metal Organic ◽  
Organic Chemical Vapor Deposition ◽  
Ethyl Amine

ABSTRACTIt has been recently shown that high quality ZnSe and ZnTc filns can be grown on GaAs using low temperature growth techniques such as Metal-Organic Chemical Vapor Deposition ( MOCVD). All samples: ZnSe, ZnTe, ZnSc(l−x)Tc(x) epilayers and ZnSe/ZnTc superlattices were grown using a novel zinc precursor, the Tri-Ethyl-Amine Di-Methyl-Zinc, while we used the classical precursors H2Se and Di-Isopropyl-Tellurium for selenium and tellurium. Investigation of the photoluminescence (PL) properties of ZnSc and ZnTe single layers enabled us to optimize the growth conditions of these compounds. The crystal growth conditions for mixed alloys and superlattices were determined by direct comparison to the aspect of low-temperature PL features. Strong PL spectra were obtained from these materials, suggesting us that tellurium has the ability to behave like an iso-clectronic center. At low concentration of tellurium in ZnSe, an interesting physical situation is observed, which we have interpreted in terms of extrinsic exciton “self-trapping” mechanism.

Structural and Defect Study of Low Temperature INP Grown by Gas Source Molecular Beam Epitaxy

1991 ◽  
Vol 241 ◽  
Author(s):  
J. Ch. Garcia ◽  
J. P. Hirtz ◽  
P. Maurel ◽  
H. J. Von Bardeleben ◽  
J. C. Bourgoin
Keyword(s):  
Molecular Beam Epitaxy ◽  
Low Temperature ◽  
Molecular Beam ◽  
Secondary Ion Mass Spectrometry ◽  
Group V ◽  
Temperature Growth ◽  
Low Temperature Growth ◽  
Gas Source ◽  
High Concentrations ◽  
Secondary Ion

ABSTRACTThe low temperature growth procedure used in the case of GaAs to introduce high concentrations of deep traps such as arsenic antisite defects has been extended to the growth of InP by gas source molecular beam epitaxy. The low temperature growth of InP induces a strong group V stoechiometric deviation (of the order of +1%). On the other hand, Secondary Ion Mass Spectrometry reveals high levels of hydrogen ranging from 3.1018 to 3.1019 cm−3 depending on growth temperature. Undoped layers are found to be resistive without any post annealing. Annealing experiments above 250°C lead to conductive layers suggesting a passivation effect of both shallow donors and acceptors by hydrogen.

The Shape Control of ZnO Based Nanostructures

2006 ◽  
Vol 6 (11) ◽  
pp. 3628-3632
Author(s):  
M. N. Jung ◽  
S. Y. Ha ◽  
H. S. Kim ◽  
H. J. Ko ◽  
H. Ko ◽  
...  
Keyword(s):  
Growth Temperature ◽  
Shape Control ◽  
Deep Level ◽  
Growth Parameters ◽  
Stoichiometric Composition ◽  
Growth Conditions ◽  
Second Phase ◽  
Gas Flux ◽  
Carrier Gas ◽  
Si Substrates

Tetrapod-shape ZnO nanostructures are formed on Si substrates by vapor phase transportation method. The effects of two important growth parameters, growth temperature and VI/II ratio, are investigated. The growth temperature is varied in the range from 600 °C to 900 °C to control the vapor pressure of group II-element and the formation process of nanostructures. VI/II ratio was changed by adjusting the flux of carrier gas which affects indirectly the supplying rate of group VI-element. From the scanning electron microscopy (SEM), systematic variation of shape including cluster, rod, wire and tetrapod was observed. ZnO tetrapods, formed at 800 °C under the carrier gas flux of 0.5 cc/mm2 min, show considerably uniform shape with 100 nm thick and 1 ∼ 1.5 μm long legs. Also stoichiometric composition (O/Zn ∼ 1) was observed without any second phase structures. While, the decrease of growth temperature and the increase of carrier gas flux, results in the irregular shaped nanostructures with non-stoichiometric composition. The excellent luminescence properties, strong excitonic UV emission at 3.25 eV without deep level emission, indicate that the high crystalline quality tetrapod structures can be formed at the optimized growth conditions.

Atomic Layer Epitaxy of GaAs on Ge Substrates

1989 ◽  
Vol 163 ◽  
Author(s):  
J. Ramdani ◽  
B.T. Mcdermott ◽  
S.M. Bedair
Keyword(s):  
Low Temperature ◽  
Growth Temperature ◽  
Adsorption Process ◽  
Substantial Reduction ◽  
Atomic Layer ◽  
Atomic Layer Epitaxy ◽  
Temperature Growth ◽  
Low Temperature Growth ◽  
Low Temperature Deposition ◽  
Temperature Deposition

AbstractWe report on the low temperature growth of GaAs on Ge substrates using Atomic Layer Epitaxy. Low temperature deposition has resulted in substantial reduction of the outdiffusion of Ge into the GaAs epilayer as being indicated from SIMS. The I-V characteristics of the GaAs/Ge heterojunction were thyristor like or near abrupt depending on the growth temperature. We also report on the use of the Atomic Layer Epitaxy self-limiting adsorption process of TMGa to control the diffusion of Ga into Ge substrates at the monolayer level.

scholarly journals Plasma-Enhanced Chemical Vapor Deposition of Acetylene on Codeposited Bimetal Catalysts Increasing Graphene Sheet Continuity Under Low-Temperature Growth Conditions

2019 ◽  
Vol 14 (1) ◽  
Author(s):  
Joshua Tracy ◽  
Otto Zietz ◽  
Samuel Olson ◽  
Jun Jiao
Keyword(s):  
Chemical Vapor Deposition ◽  
Low Temperature ◽  
Vapor Deposition ◽  
Inductively Coupled Plasma ◽  
Chemical Vapor ◽  
Growth Conditions ◽  
Monolayer Graphene ◽  
Au Catalyst ◽  
Temperature Growth ◽  
Low Temperature Growth

Abstract Here, we report a novel method for low-temperature synthesis of monolayer graphene at 450 °C on a polycrystalline bimetal Ni-Au catalyst. In this study, low-temperature chemical vapor deposition synthesis of graphene was performed at 450 °C on codeposited Ni-Au which shows successful monolayer graphene formation without an extra annealing process. The experimental results suggest that electron beam codeposition of bimetal catalyst is the key procedure that enables the elimination of the pre-growth high-temperature annealing of the catalyst prior to graphene synthesis, an indispensable process, used in previous reports. The formation was further improved by plasma-assisted growth in which the inductively coupled plasma ionizes the carbon precursors that interact with codeposited Ni-Au catalyst of 50 nm in thickness at 450 °C. These combined growth conditions drastically increase the graphene’s sheet uniformity and area connectivity from 11.6% to 99%. These fabrication parameters enable the graphene formation that shifts from a bulk diffusion-based growth model towards a surface based reaction. The technique reported here opens the opportunity for the low-temperature growth of graphene for potential use in future CMOS applications.

Low-temperature growth of ZnO nanowires

2003 ◽  
Vol 18 (3) ◽  
pp. 714-718 ◽  
Author(s):  
Yung-Kuan Tseng ◽  
I-Nan Lin ◽  
Kuo-Shung Liu ◽  
Tzer-Shen Lin ◽  
I-Cherng Chen
Keyword(s):  
Low Temperature ◽  
Near Infrared ◽  
Gold Catalyst ◽  
Zno Nanowires ◽  
Near Band Edge ◽  
Band Edge Emission ◽  
Wurtzite Phase ◽  
Ultraviolet Emission ◽  
Temperature Growth ◽  
Low Temperature Growth

ZnO nanowires with diameters of 40–200 nm were grown with a gold catalyst in bulk quantities on alumina substrates and sapphire substrates. This synthesis procedure was achieved by heating a 1:1 mixture of ZnO and Zn powder to 500 °C with trace water vapor as an oxidizer. X-ray diffraction and transmission electron microscopy revealed that the nanowires were in the pure wurtzite phase. Photoluminescence spectroscopy showed two peaks: one was a strong ultraviolet emission at around 380 nm, which corresponds to the near-band-edge emission; the other was a weak near-infrared emission around 750 nm, which indicates a low concentration of oxygen vacancy. Moreover, we observed that the Zn/Au alloy droplets appeared on the tips of ZnO nanowires. As a consequence, we can select areas to grow ZnO nanowires by patterning the thin metal film on the substrates. These findings prove that the low-temperature growth mechanism is via vapor–liquid–solid rather than vapor transport deposition or vapor supersaturation (vapor–solid) mechanism. On the basis of the site-specific growth and the low-temperature requirement developed from this work, the synthesis of ZnO is compatible to microelectric machining system processing.

Role of boundaries in the crystallization of amorphous films

1988 ◽  
Vol 46 ◽  
pp. 626-627
Author(s):  
D. A. Smith
Keyword(s):  
Low Temperature ◽  
Amorphous State ◽  
Nucleation And Growth ◽  
Amorphous Films ◽  
Island Nucleation ◽  
Surface Steps ◽  
Transmission Electron ◽  
Component Systems ◽  
Temperature Deposition

The nucleation and growth processes which lead to the formation of a thin film are particularly amenable to investigation by transmission electron microscopy either in situ or subsequent to deposition. In situ studies have enabled the observation of island nucleation and growth, together with addition of atoms to surface steps. This paper is concerned with post-deposition crystallization of amorphous alloys. It will be argued that the processes occurring during low temperature deposition of one component systems are related but the evidence is mainly indirect. Amorphous films result when the deposition conditions such as low temperature or the presence of impurities (intentional or unintentional) preclude the atomic mobility necessary for crystallization. Representative examples of this behavior are CVD silicon grown below about 670°C, metalloids, such as antimony deposited at room temperature, binary alloys or compounds such as Cu-Ag or Cr O2, respectively. Elemental metals are not stable in the amorphous state.

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