Compensation by deep levels in semi-insulating GaAs

1982 ◽  
Vol 60 (1) ◽  
pp. 35-40 ◽  
Author(s):  
B. A. Lombos ◽  
N. Yemenidjian ◽  
M. Averous
Keyword(s):  
Fermi Level ◽  
Multilevel Model ◽  
Deep Levels ◽  
High Resistivity ◽  
Spectrographic Analysis ◽  
Insulating Materials ◽  
Active Impurity ◽  
Source Mass ◽  
Insulating Properties

A multilevel model was developed to calculate the position of the Fermi level in GaAs. All the electrically-active impurity concentrations, indicated by spark source mass spectrographic analysis, were taken into account in the computation. The deduced semiconducting or semi-insulating properties are in agreement with the measured characteristics of the investigated crystals. It is shown that, in the case of the large gap semiconductors, only deep-lying impurity compensation results in high resistivity, semi-insulating materials.

Deep levels in high resistivity GaN epilayers grown by MOCVD

2006 ◽  
Vol 3 (3) ◽  
pp. 585-588 ◽  
Author(s):  
Cebao Fang ◽  
Xiaoliang Wang ◽  
Junxi Wang ◽  
Chao Liu ◽  
Cuimei Wang ◽  
...  
Keyword(s):  
Deep Levels ◽  
High Resistivity

Deep Level Centers in Carbon-Doped High Resistivity GaN

2014 ◽  
Vol 997 ◽  
pp. 492-495
Author(s):  
Huan Cui ◽  
Li Wu Lu ◽  
Ling Sang ◽  
Bai He Chen ◽  
Zhi Wei He ◽  
...  
Keyword(s):  
Deep Level ◽  
Chemical Vapor ◽  
Deep Levels ◽  
Hall Measurement ◽  
High Resistivity ◽  
Organic Chemical ◽  
Carbon Doped ◽  
Metal Organic ◽  
High Level ◽  
Organic Chemical Vapor Deposition

The deep levels of carbon doped high resistivity (HR) GaN samples grown by metal-organic chemical vapor deposition (MOCVD) has been investigated using thermally stimulated current (TSC) spectroscopy and high temperature (HT) Hall measurement. Two different thickness of 100 and 300 nm were used to be compared. It was found that four distinct deep levels by TSC and one deep level by HT Hall measurement were observed in both samples, which means great help for the decrease of leakage current and lifetime limitations of device utilizing the structure. The activation energy of these levels was calculated and their possible origins were also proposed. The low temperature traps, might be related to VN, 0.50 and 0.52eV related to incorporate a high level carbon, 0.57eV related to VGa, 0.59eV related to CGaor NGa, 0.91 and 0.97eV related to interstitial N1.

Investigation of Deep Levels In X-Ray Detector Material With Photo Induced Current Transient Spectroscopy (Picts)

1993 ◽  
Vol 302 ◽  
Author(s):  
C Eiche ◽  
M Fiederle ◽  
J Weese ◽  
D Maier ◽  
D Ebling ◽  
...  
Keyword(s):  
Tikhonov Regularization ◽  
Deep Level ◽  
Great Influence ◽  
Simulated Data ◽  
Radiation Detectors ◽  
Deep Levels ◽  
High Resistivity ◽  
Pulse Excitation ◽  
Detector Performance ◽  
Transient Spectroscopy

ABSTRACTDeep levels have a great influence on the recombination behavior of the free carriers in semiconductors. For several years PICTS has been used to investigate the deep levels in high resistivity material such as GaAs or CdTe used in detector applications. An important feature of the PICTS measurements is the analysis of the current transients after pulse excitation. We propose using a new method based on Tikhonov regularization. This method was implemented in the program FTIKREG (Fast Tikhonov Regularization) by one of the authors. The superior resolution of the regularization method in comparison to conventional techniques is shown using simulated data. Moreover, the method is applied to investigate deep levels in CdTe:Cl, SI-GaAs and GaAs:Cr samples used for room temperature radiation detectors. A relation between deep level properties and detector performance is proposed.

Light-Weight and High Thermal Insulating EPDM Composites Modified with Pretreated Hollow Phenolic Micro-Spheres

2013 ◽  
Vol 750-752 ◽  
pp. 140-145
Author(s):  
Zi Gao Zeng ◽  
Xiao Long Jia ◽  
Xiao Ping Yang ◽  
Jun Yi Zheng ◽  
Wu Sheng Li
Keyword(s):  
Specific Gravity ◽  
High Performance ◽  
Layer Structure ◽  
Light Weight ◽  
Insulating Materials ◽  
Thermal Insulating ◽  
Uniform Dispersion ◽  
Micro Sphere ◽  
New Generation ◽  
Insulating Properties

High performance thermal insulating ethylene-propylene-diene monomer (EPDM) composites were obtained with the addition of hollow phenolic micro-sphere. The effects of the pretreatment and content of micro-sphere on various properties of EPDM composites were evaluated. Experimental results showed that thermal conductivity and specific gravity of EPDM composites significantly decreased, which was due to the intact and uniform dispersion of pretreated micro-sphere throughout the EPDM matrix. With the content increasing of pretreated micro-sphere, the specific gravity of EPDM composites linearly decreased while the thermal stability increased. Specifically, EPDM composites showed the three-layer structure after ablation and the addition of pretreated micro-sphere distinctively enhanced thermal insulating properties of EPDM composites, which was attributed to multi-type heat conductivity resulted from hollow micro-spheres. Hollow phenolic micro-sphere exhibited great potential in preparing new generation of light-weight and high thermal insulating materials.

Semi‐insulating properties of Fe‐implanted InP. II. Deep levels of Fe from the study ofp+‐semi‐insulating‐n+diodes

1985 ◽  
Vol 58 (5) ◽  
pp. 1787-1797 ◽  
Author(s):  
Julian Cheng ◽  
S. R. Forrest ◽  
B. Tell ◽  
D. Wilt ◽  
B. Schwartz ◽  
...  
Keyword(s):  
Deep Levels ◽  
Insulating Properties

Cement Based Heat-Insulating Materials for Use in Floor Constructions

2016 ◽  
Vol 865 ◽  
pp. 224-228
Author(s):  
Karel Mikulica ◽  
Iveta Hájková ◽  
Adam Hubáček
Keyword(s):  
Liquid State ◽  
Cement Mortar ◽  
Construction Materials ◽  
Construction Site ◽  
Insulating Materials ◽  
Load Bearing ◽  
Insulating Material ◽  
Hardened State ◽  
Optimum Heating ◽  
Insulating Properties

Many architects, designers and builders struggle with the ongoing problem of how to fill the space between the load bearing foundations / ceiling land the flooring structure in the easiest and cheapest way while still retaining the optimum heating and sound insulating properties. In this age of hi-tech and plentiful amounts of construction materials, it is very difficult to focus on the market. On paper, very similar products from natural or artificially produced materials can be delivered to the construction site in a hardened state, most frequently in the form of boards or granulate or produced directly on-site or near a concrete plant and transported to for placement in a liquid state. This areas does concerns both new residential or industrial objects, as we as old objects which are waiting for reconstruction. During the project solution, various mixtures were designed that use the cement mortar and filler as a binder in the form of technical foam, expanded clay, vermiculite, perlite and hemp shives, so that when fresh the density does not exceed 1.400 kg / m3 and the materials can then be used as heat-insulating material in the flooring construction.

Dependence of the Sn0/2+ charge state on the Fermi level in semi-insulating CdTe

2007 ◽  
Vol 22 (11) ◽  
pp. 3249-3254 ◽  
Author(s):  
V. Babentsov ◽  
J. Franc ◽  
H. Elhadidy ◽  
A. Fauler ◽  
M. Fiederle ◽  
...  
Keyword(s):  
Fermi Level ◽  
Charge State ◽  
Strong Dependence ◽  
High Resistivity ◽  
Level Variation ◽  
Radiative Transitions ◽  
Deep Traps ◽  
First Time ◽  
Positively Charged

We explored the growth and characteristics of CdTe doped with Sn to heighten our understanding of the role of deep levels on electrical compensation and trapping. We demonstrated, for the first time, the strong dependence of the SnCd charge state on the Fermi-level variation (2–3kT) in high-resistivity CdTe. The concentration of deep traps for electrons was determined by the number of doubly positively charged Sn2+ atoms. Thermoelectric-effect spectroscopy and photovoltage measurements revealed the conversion of the SnCd defect from the electron SnCd2+ trap to the hole SnCd0 trap. The results agree well with the existence of a negative U-center in the SnCd0/2+ defect. We also showed that the neutral Sn defect is responsible for the near midgap C-band → bound hole radiative transitions band with a maximum at 0.76 eV.

Effect of Humidity on Partial Discharge Characteristics of Epoxy/Boron Nitride Nanocomposite under High Voltage Stress

2017 ◽  
Vol 7 (3) ◽  
pp. 1562
Author(s):  
Noor ‘Aliaa Awang ◽  
Faris Akmal Suhaini ◽  
Yanuar Z. Arief ◽  
Mohd Hafizi Ahmad ◽  
Noor Azlinda Ahmad ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Boron Nitride ◽  
High Voltage ◽  
Surface Resistance ◽  
Ageing Time ◽  
Partial Discharge ◽  
Discharge Characteristics ◽  
Insulating Materials ◽  
Voltage Stress ◽  
Insulating Properties

Partial discharge (PD) may lead to the degradation of insulating materials and affect the lifetime of high voltage equipment. This paper describes the effect of relative humidity on PD characteristic of epoxy/boron nitride (BN) nanocomposite under high voltage (HV) stress. In this work, CIGRE Method II was utilized as an electrode configuration. BN nanofiller was chosen because of its high insulating properties with high thermal conductivity. The PD characteristics such as PD charge magnitude, PD number or occurrence, and average of PD charge during certain of ageing time under HV stress against relative humidity were examined. The results revealed that PD number of humid samples is higher about 8~14% compared to the normal ones. It is considered due to the decrease of surface resistance of the humid samples. The PD charge magnitudes of humid samples are slightly higher compared to the normal ones. The epoxy/BN nanocomposite has lesser PD number and magnitude compared to the neat epoxy samples.

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