Efficient Nonradiative Recombination Centers in MBE-Grown Si and SiGe/Si Heterostructures

1995 ◽  
Vol 378 ◽  
Author(s):  
W. M. Chen ◽  
I. A. Buyanova ◽  
A. Henry ◽  
W.-X. Ni ◽  
G. V. Hansson ◽  
...  
Keyword(s):  
Growth Conditions ◽  
Nonradiative Recombination ◽  
Mbe Growth ◽  
Temperature Growth ◽  
Positive Ions ◽  
Carrier Recombination ◽  
Recombination Processes ◽  
Nonradiative Defect ◽  
Recombination Centers ◽  
Low Symmetry

AbstractWe carry out an investigation of grown-in nonradiative defects in Si and SiGe/Si heterostructures grown by molecular-beam-epitaxy (MBE). A number of such defects are observed by the optical detection of magnetic resonance (ODMR) technique, in samples with various structures and growth conditions. These defects are shown to provide efficient nonradiative shunt paths for carrier recombination, competing with and reducing radiative recombination processes. It is revealed that the dominant nonradiative defect is a low-symmetry vacancy-related complex, evident from a characteristic hyperfine structure due to 29Si ligands (with nuclear spin I=1/2 and natural abundance of 4.67 %) connected to the dangling bonds. The introduction of these defects is believed to be largely due to a low surface adatom mobility during the low temperature growth. By varying the substrate bias during the MBE growth, it is shown that the formation of these nonradiative defects can be effectively enhanced by exposure to accelerated positive ions, presumably dominated by the Si+ ions. Effects of hydrogenation on these defects are also studied.

Roles of carbon impurities and intrinsic nonradiative recombination centers on the carrier recombination processes of GaN crystals

2019 ◽  
Vol 13 (1) ◽  
pp. 012004 ◽  
Author(s):  
Kazunobu Kojima ◽  
Fumimasa Horikiri ◽  
Yoshinobu Narita ◽  
Takehiro Yoshida ◽  
Hajime Fujikura ◽  
...  
Keyword(s):  
Nonradiative Recombination ◽  
Carrier Recombination ◽  
Carbon Impurities ◽  
Recombination Processes ◽  
Recombination Centers

Influence Of Growth Conditions On The Thermal Quenching Of Photoluminescence From Sige/Si Quantum Structures

1998 ◽  
Vol 533 ◽  
Author(s):  
I. A. Buyanova ◽  
W. M. Chen ◽  
W.-X. Ni ◽  
G. V. Hansson ◽  
B. Monemar
Keyword(s):  
High Temperature ◽  
Quantum Wells ◽  
Growth Temperature ◽  
Thermal Activation ◽  
Molecular Beam ◽  
Thermal Quenching ◽  
Growth Conditions ◽  
Mbe Growth ◽  
Temperature Growth ◽  
Optically Detected

AbstractIn this work we study effects of growth temperature and use of surfactant during growth on thermal quenching of photoluminescence (PL) from SiGe/Si quantum wells (QWs) grown by molecular beam epitaxy (MBE). We show that although all investigated structures demonstrate intense and sharp excitonic emissions from the SiGe QWs at liquid helium temperature, thermal quenching of this PL critically depends on the growth conditions. In particular, the use of low (⁤ 550°C) growth temperatures or employing Sb as a surfactant during high temperature (620°C) growth considerably degrades the PL thermal quenching behaviour by introducing some competing quenching processes with low activation energies of about 5 meV. The optimum growth conditions judging from the PL thermal behaviour are realised during high temperature growth without surfactant (620°C). Even higher growth temperature is shown to be required during surfactant mediated growth to improve the thermal quenching behaviour. From optically detected magnetic resonance (ODMR) studies, the competing quenching processes are attributed to a thermal activation of non-radiative defects introduced during either low-temperature MBE growth or during surfactant-mediated growth.

Effect of Nitrogen Flux on the Properties of N-Doped Zn1-xMgxO Thin Films

2017 ◽  
Vol 900 ◽  
pp. 83-88
Author(s):  
Wei Wei Liu ◽  
Cheng Lin Liu ◽  
Hong Xia Chen ◽  
Rong Wang
Keyword(s):  
Thin Films ◽  
Hole Concentration ◽  
Growth Conditions ◽  
Emission Peak ◽  
Nonradiative Recombination ◽  
Nitrogen Flux ◽  
Uv Emission ◽  
Recombination Centers ◽  
P Type ◽  
Mg Content

Different Mg content in Zn1-xMgxO was also obtained by varying N2 flux. UV emission peak in photoluminescence (PL) spectra shift from 350 nm to 360 nm, and then to 352 nm, which is consistent with the result of absorption spectra of the Zn1-xMgxO:N films grown at different N2 flux. The emission intensity of the Zn1-xMgxO:N band edge peak was drastically reduced with increasing N2 flux, which was attributed to the concentration of nonradiative recombination centers increased with increasing N2 flux. The carrier concentration of N-doped Zn1-xMgxO increased with increasing N2 flux below 0.8 sccm, while those above 0.8 sccm decreased. The p-type Zn1-xMgxO:N with the maximum hole concentration 3.97×1017 cm-3 was obtained by optimizing growth conditions.

Nature and Formation of Non-Radiative Defects in GaNAs And InGaAsN

2001 ◽  
Vol 692 ◽  
Author(s):  
W. M. Chen ◽  
N. Q. Thinh ◽  
I. A. Buyanova ◽  
P. N. Hai ◽  
H. P. Xin ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Radiative Recombination ◽  
Molecular Beam ◽  
Deep Level ◽  
The Other ◽  
Temperature Growth ◽  
Carrier Recombination ◽  
Recombination Centers ◽  
Optically Detected

AbstractThe optically detected magnetic resonance (ODMR) technique has been employed to examine the nature and formation mechanism of non-radiative defects in GaNAs and InGaAsN. In both alloys, two defects were observed and were shown to be deep-level, non-radiative recombination centers. One of the defects has been identified as a complex involving an AsGa antisite. These two defects gain more importance with increasing N composition up to 3%, presumably due to an increase in their concentration. With a further higher N composition, the defects start to lose importance in carrier recombination that is attributed to an increasingly important role of other new non-radiative channels introduced with a high N composition. On the other hand, effect of In composition up to 3% seems to be only marginal. Both defects were shown to be preferably introduced in the alloys during low-temperature growth by molecular beam epitaxy (MBE), but can be rather efficiently removed by post-growth rapid thermal annealing.

Influence of MBE Growth Conditions on Dislocation Densities of GaAs/Ge Epilayers Grown on Silicon Substrates

1985 ◽  
Vol 43 ◽  
pp. 364-365
Author(s):  
K.M. Hones ◽  
P. Sheldon ◽  
B.G. Yacobi ◽  
A. Mason
Keyword(s):  
High Efficiency ◽  
Lattice Mismatch ◽  
Low Cost ◽  
Growth Conditions ◽  
Nonradiative Recombination ◽  
Device Structure ◽  
Si Substrates ◽  
Transmission Electron ◽  
Dislocation Densities ◽  
Dislocation Type

There is increasing interest in growing epitaxial GaAs on Si substrates. Such a device structure would allow low-cost substrates to be used for high-efficiency cascade- junction solar cells. However, high-defect densities may result from the large lattice mismatch (∼4%) between the GaAs epilayer and the silicon substrate. These defects can act as nonradiative recombination centers that can degrade the optical and electrical properties of the epitaxially grown GaAs. For this reason, it is important to optimize epilayer growth conditions in order to minimize resulting dislocation densities. The purpose of this paper is to provide an indication of the quality of the epitaxially grown GaAs layers by using transmission electron microscopy (TEM) to examine dislocation type and density as a function of various growth conditions. In this study an intermediate Ge layer was used to avoid nucleation difficulties observed for GaAs growth directly on Si substrates. GaAs/Ge epilayers were grown by molecular beam epitaxy (MBE) on Si substrates in a manner similar to that described previously.

Growth of Epitaxial IrSi3 Layers on Si(111)

1989 ◽  
Vol 160 ◽  
Author(s):  
T. L. Lin ◽  
C. W. Nieh
Keyword(s):  
Surface Morphology ◽  
Molecular Beam ◽  
Solid Phase ◽  
Single Mode ◽  
Growth Conditions ◽  
Tem Analysis ◽  
Mbe Growth ◽  
Good Surface ◽  
Transmission Electron

AbstractEpitaxial IrSi3 films have been grown on Si (111) by molecular beam epitaxy (MBE) at temperatures ranging from 630 to 800 °C and by solid phase epitaxy (SPE) at 500 °C. Good surface morphology was observed for IrSi3 layers grown by MBE at temperatures below 680 °C, and an increasing tendency to form islands is noted in samples grown at higher temperatures. Transmission electron microscopy (TEM) analysis reveals that the IrSi3 layers grow epitaxially on Si(111) with three epitaxial modes depending on the growth conditions. For IrSi3 layers grown by MBE at 630 °C, two epitaxial modes were observed with ~ 50% area coverage for each mode. Single mode epitaxial growth was achieved at a higher MBE growth temperature, but with island formation in the IrSi3 layer. A template technique was used with MBE to improve the IrSi3 surface morphology at higher growth temperatures. Furthermore, single-crystal IrSi3 was grown on Si(111) at 500 °C by SPE, with annealing performed in-situ in a TEM chamber.

Efficient Defect Passivation with Niacin for High-Performance and Stable Perovskite Solar Cells

2021 ◽  
Author(s):  
Jing Ren ◽  
Shurong Wang ◽  
Jianxing Xia ◽  
Chengbo Li ◽  
Lisha Xie ◽  
...  
Keyword(s):  
Solar Cells ◽  
Charge Carrier ◽  
High Performance ◽  
Perovskite Solar Cells ◽  
Trap States ◽  
Carrier Recombination ◽  
Defect Passivation ◽  
Recombination Centers ◽  
Charge Carrier Recombination ◽  
Halide Perovskite

Defects, inevitably produced in the solution-processed halide perovskite films, can act as charge carrier recombination centers to induce severe energy loss in perovskite solar cells (PSCs). Suppressing these trap states...

scholarly journals Numerical study on the optical and carrier recombination processes in GeSn alloy for E-SWIR and MWIR optoelectronic applications

2016 ◽  
Vol 24 (23) ◽  
pp. 26363 ◽  
Author(s):  
Stefano Dominici ◽  
Hanqing Wen ◽  
Francesco Bertazzi ◽  
Michele Goano ◽  
Enrico Bellotti
Keyword(s):  
Numerical Study ◽  
Carrier Recombination ◽  
Recombination Processes ◽  
Optoelectronic Applications ◽  
Gesn Alloy

Formation of Cr-rich Nano-clusters and Columns in (Zn,Cr)Te Grown by MBE

2009 ◽  
Vol 1183 ◽  
Author(s):  
Yôtarõ Nishio ◽  
Kôichirô Ishikawa ◽  
Shinji Kuroda ◽  
Masanori Mitome ◽  
Yoshio Bando
Keyword(s):  
Magnetic Properties ◽  
Substrate Temperature ◽  
Crystallographic Orientation ◽  
Vertical Direction ◽  
Growth Conditions ◽  
Chemical Analyses ◽  
Mbe Growth ◽  
One Dimensional ◽  
X Ray ◽  
Cr Content

AbstractThe correlation between the Cr aggregation and magnetic properties are investigated for the series of Zn1-xCrxTe films grown by MBE with a systematic variation of growth conditions. Structural and chemical analyses using TEM and energy-dispersive X-ray spectroscopy (EDS) reveal that the crystallinity and the Cr distribution change significantly with the substrate temperature during the MBE growth. For a relatively low average Cr content x ≅ 0.05, it is found that the crystal quality is improved with the increase of the substrate temperature. For a higher average Cr content x ≅ 0.2, the shape of Cr-rich regions is transformed from isolated clusters into one-dimensional nanocolumns with the increase of the substrate temperature. The direction of the nanocolumn formation changes depending on the crystallographic orientation of the grown films. In the magnetization measurements, anisotropic magnetic properties are observed in the films in which Cr-rich nanocolumns are formed in the vertical direction, depending on the relation between the direction of the nanocolumns and the applied magnetic fields.

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