Deep Level Defects, Luminescence, and the Electro-Optic Properties of SiGe/Si Heterostructures

1993 ◽  
Vol 325 ◽  
Author(s):  
Pallab Bhattaci-Iarya ◽  
Shin-Hwa Li ◽  
Jinju Lee ◽  
Steve Smith
Keyword(s):  
Quantum Wells ◽  
Cross Sections ◽  
Quantum Wires ◽  
Deep Level ◽  
Luminescent Properties ◽  
Deep Levels ◽  
Electro Optic ◽  
B Doping ◽  
P Type ◽  
Capture Cross Sections

AbstractDeep levels and luminescence in SiGe/Si heterostructures and quantum wells have been investigated. We have studied the effects of Be- and B-doping on the luminescent properties of Si1−xGex/Si single and multiquantum wells. No new levels, or enhancement of luminescence, from that in undoped samples, is detected in samples which are selectively doped in the well-regions, implying that the observed luminescence in the undoped quantum wells is a result of alloy disordering. Slight enhancement of luminescence is observed in disordered wells and in quantum wires made by electron beam lithography and dry etching. Deep levels have been identified and characterized in undoped Si1-xGex alloys. Hole traps in the p-type layers have activation energies ranging from 0.029-0.45 eV and capture cross sections (σ∞) ranging from 10−9 to 10−20 cm2. Possible origins of these centers are discussed. Some possibilities of obtaining enhanced electro-optic coefficients in SiGe/Si heterostructures are discussed.

Reactive-Ion-Etching Induced Deep Levels Observed in n-Type and p-Type 4H-SiC

2010 ◽  
Vol 645-648 ◽  
pp. 759-762
Author(s):  
Koutarou Kawahara ◽  
Giovanni Alfieri ◽  
Michael Krieger ◽  
Tsunenobu Kimoto
Keyword(s):  
Deep Level Transient Spectroscopy ◽  
Deep Level ◽  
Reactive Ion Etching ◽  
Deep Levels ◽  
Total Density ◽  
Ion Etching ◽  
Initial Concentration ◽  
Grown Sample ◽  
Transient Spectroscopy ◽  
P Type

In this study, deep levels are investigated, which are introduced by reactive ion etching (RIE) of n-type/p-type 4H-SiC. The capacitance of as-etched p-type SiC is remarkably small due to compensation or deactivation of acceptors. These acceptors can be recovered to the initial concentration of the as-grown sample after annealing at 1000oC. However, various kinds of defects remain at a total density of ~5× 1014 cm-3 in a surface-near region from 0.3 μm to 1.0 μm even after annealing at 1000oC. The following defects are detected by Deep Level Transient Spectroscopy (DLTS): IN2 (EC – 0.35 eV), EN (EC – 1.6 eV), IP1 (EV + 0.35 eV), IP2 (HS1: EV + 0.39 eV), IP4 (HK0: EV + 0.72 eV), IP5 (EV + 0.75 eV), IP7 (EV + 1.3 eV), and EP (EV + 1.4 eV). These defects generated by RIE can be significantly reduced by thermal oxidation and subsequent annealing at 1400oC.

Shallow and Deep Level Defects in GaN

1995 ◽  
Vol 395 ◽  
Author(s):  
W. Götz ◽  
N.M. Johnson ◽  
D.P. Bour ◽  
C. Chen ◽  
H. Liu ◽  
...  
Keyword(s):  
Deep Level ◽  
Variable Temperature ◽  
Shallow Donor ◽  
Deep Levels ◽  
Electron Photoemission ◽  
Hall Effect Measurements ◽  
Transient Spectroscopy ◽  
P Type ◽  
Capacitance Transient ◽  
Threshold Energies

ABSTRACTShallow and deep electronic defects in MOCVD-grown GaN were characterized by variable temperature Hall effect measurements, deep level transient spectroscopy (DLTS) and photoemission capacitance transient spectroscopy (O-DLTS). Unintentionally and Si-doped, n-type and Mg-doped, p-type GaN films were studied. Si introduces a shallow donor level into the band gap of GaN at ∼Ec - 0.02 eV and was found to be the dominant donor impurity in our unintentionally doped material. Mg is the shallowest acceptor in GaN identified to date with an electronic level at ∼Ev + 0.2 eV. With DLTS deep levels were detected in n-type and p-type GaN and with O-DLTS we demonstrate several deep levels with optical threshold energies for electron photoemission in the range between 0.87 and 1.59 eV in n-type GaN.

Meyer-Neldel Rule in Deep-Level-Transient-Spectroscopy and its Ramifications

2003 ◽  
Vol 763 ◽  
Author(s):  
Richard S. Crandall
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Deep Level Transient Spectroscopy ◽  
Deep Level ◽  
Capture Cross ◽  
Emission Data ◽  
The Cross ◽  
Transient Spectroscopy ◽  
Capture Cross Sections

AbstractThis paper presents data showing a Meyer-Neldel rule (MNR) in InGaAsN alloys. It is shown that without this knowledge, significant errors will be made using Deep-Level Transient-Spectroscopy (DLTS) emission data to determine capture cross sections. By correctly accounting for the MNR in analyzing the DLTS data the correct value of the cross section is obtained.

Deep Levels in P-Type 4H-SiC Induced by Low-Energy Electron Irradiation

2013 ◽  
Vol 740-742 ◽  
pp. 373-376 ◽  
Author(s):  
Kazuki Yoshihara ◽  
Masashi Kato ◽  
Masaya Ichimura ◽  
Tomoaki Hatayama ◽  
Takeshi Ohshima
Keyword(s):  
Electron Irradiation ◽  
Deep Level Transient Spectroscopy ◽  
Deep Level ◽  
Deep Levels ◽  
Low Energy ◽  
Epitaxial Layers ◽  
Before And After ◽  
Low Energy Electron ◽  
Transient Spectroscopy ◽  
P Type

We have characterized deep levels in as-grown and electron irradiated p-type 4H-SiC epitaxial layers by the current deep-level transient spectroscopy (I-DLTS) method. A part of the samples were irradiated with electrons in order to introduce defects. As a result, we found that electron irradiation to p-type 4H-SiC created complex defects including carbon vacancy or interstitial. Moreover, we found that observed deep levels are different between before and after annealing, and thus annealing may change structures of defects.

Observation of the Influence of Strain Induced deep Level Defects on the Electroabsorption Characteristics of InGaAs/GaAs (100) Multiple Quantum well Structures and Implications for Light Modulators

1991 ◽  
Vol 240 ◽  
Author(s):  
Li Chen ◽  
Wei Chen ◽  
K. C. Rajkumar ◽  
Kezhong Hu ◽  
A. Madhukar
Keyword(s):  
Reverse Bias ◽  
Deep Level ◽  
Free Exciton ◽  
Multiple Quantum Well ◽  
Deep Levels ◽  
Multiple Quantum ◽  
Quantum Well Structures ◽  
Light Modulators ◽  
P Type ◽  
Spatially Varying

In a thick strained GaAs/InGaAs MQW we recently reported the unusual observation of the exciton linewidth initially narrowing upon application of a reverse bias, before the usually observed broadening set in with further increase in the bias. The phenomena suggested the existence of a spatially varying electric field in the MQW region arising from a depletion of the net charge density with increasing reverse bias. Here we provide an explanation for the unusual observation arrived at through a systematic examination of the sample behavior using electro-transmission, electro-photoluminescence, capacitancevoltage profiling and transmission electron microscopy. We conclude that shallow levels cannot account for the observation and that the presence of strain induced point defect related deep levels (either n of p type) offers a consistent explanation. This is the first clear manifestation of the influence of deep levels on the free exciton electroabsorption behavior and has practical implications for MQW based electroabsorptive / electrorefractive light modulators.

Deep Levels in As-Grown and Electron-Irradiated P-type 4H-SiC

2006 ◽  
Vol 911 ◽  
Author(s):  
Katsunori Danno ◽  
Tsunenobu Kimoto
Keyword(s):  
Cross Section ◽  
Deep Level Transient Spectroscopy ◽  
Capture Cross Section ◽  
Arrhenius Plot ◽  
Deep Level ◽  
Deep Levels ◽  
Emission Time ◽  
Transient Spectroscopy ◽  
P Type ◽  
Thermal Stability Of

AbstractDeep levels in as-grown and electron-irradiated p-type 4H-SiC have been investigated by deep level transient spectroscopy (DLTS). Three hole traps, namely HK2, HK3, and HK4, could be detected in the temperature range from 350K to 700K. Activation energies of the hole traps were estimated to be 0.84 eV for HK2, 1.27 eV for HK3, and 1.44 eV for HK4 from the Arrhenius plot of emission-time constants assuming temperature-independent capture cross section. By double-correlated DLTS (DDLTS), they were revealed to be donor-like (+/0) traps. The concentrations of HK3 and HK4 centers were clearly increased by low-energy (116 keV) electron irradiation. Based on thermal stability of the HK3 and HK4 centers up to 1350°C and the dependence of HK4 concentration on the electron fluence, they may originate from a complex including defect(s) caused by carbon displacement.

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