Electrical Properties of Defects in Ga-Doped Ge Irradiated with Fast Electrons and Protons

2015 ◽  
Vol 242 ◽  
pp. 316-321
Author(s):  
Vadim V. Emtsev ◽  
Nikolay V. Abrosimov ◽  
Vitalii V. Kozlovski ◽  
Gagik A. Oganesyan
Keyword(s):  
Electrical Properties ◽  
Point Defects ◽  
Shallow Donor ◽  
Acceptor Impurity ◽  
Impurity States ◽  
Fast Electrons ◽  
Impurity Atoms ◽  
Order Of Magnitude ◽  
Donor Acceptor ◽  
P Type

Electrical properties of radiation-produced defects in p-Ge irradiated with MeV electrons and protons are investigated. The dominant defects in electron-irradiated p-Ge were found to be neutral for the most part, whereas they are electrically active in proton-irradiated materials. Evidently, the reactions between impurity atoms and intrinsic point defects leading to formation of secondary Ga-related defects in electron-and proton-irradiated p-Ge appear to be distinct. Production rates of radiation defects in n-Ge and p-Ge are compared. A marked difference in the removal rates of shallow donor/acceptor impurity states, at least by an order-of-magnitude, is thought to be due to greatly enhanced annihilation of Frenkel pairs in p-type Ge.

scholarly journals Studies on Carbon as Alternative P-Type Dopant for Gallium Nitride

1999 ◽  
Vol 4 (S1) ◽  
pp. 526-531 ◽  
Author(s):  
U. Birkle ◽  
M. Fehrer ◽  
V. Kirchner ◽  
S. Einfeldt ◽  
D. Hommel ◽  
...  
Keyword(s):  
Thermal Activation ◽  
Atomic Layer ◽  
Typical Feature ◽  
Acceptor Pair ◽  
Carbon Doped ◽  
Order Of Magnitude ◽  
Donor Acceptor ◽  
Donor Acceptor Pair ◽  
P Type ◽  
Carbon Concentrations

GaN layers were grown by molecular beam epitaxy and doped with carbon of nominal concentrations ranging from 1016 cm−3 to 1020 cm−3. The incorporation of carbon leads to a reduction of the background electron concentration by one order of magnitude but the material remains n-type. For high carbon concentrations a re-increase of the carrier concentration is observed which is related to selfcompensation. Investigations of the donor-acceptor-pair luminescence show that doping with carbon is accompanied by the generation of a new donor exhibiting a thermal activation energy of about 55 meV. Layers grown by atomic layer epitaxy are marked by an increased intensity of the donor-acceptor-pair band luminescence which is attributed to the enforced incorporation of carbon onto the nitrogen sublattice. The yellow luminescence is found to be a typical feature of all carbon doped layers in contrast to nominally undoped samples.

P- and N-Type Doping of Mbe Grown Cubic GaN/GaAs Epilayers

1998 ◽  
Vol 537 ◽  
Author(s):  
D.J. As ◽  
T. Simonsmeier ◽  
J. Busch ◽  
B. Schöttker ◽  
M. Lübbers ◽  
...  
Keyword(s):  
Low Temperature ◽  
Shallow Donor ◽  
Pressure Curve ◽  
Blue Band ◽  
Vapor Pressure Curve ◽  
Cubic Gan ◽  
Donor Acceptor ◽  
Hall Effect Measurements ◽  
Si Doped ◽  
P Type

AbstractP-type doping with Mg and n-type doping with Si of cubic GaN (c-GaN) epilayers is reported. Cubic GaN films are grown by if-plasma assisted MBE on semi-insulating GaAs (001) substrates at a substrate temperature of 720°C. Elemental Mg and Si are evaporated from thermal effusions cells. Secondary ion mass spectroscopy (SIMS), low temperature photoluminescence (PL) and temperature dependent Hall-effect measurements are used to study the incorporation, optical and electrical properties. A Mg related shallow donor-acceptor transiton at 3.04 eV with an acceptor activation energy of EA= 0.230 eV is observed by low temperature PL. At Mg concentrations above 1018 cm-3 the dominance of a broad blue band indicates that also in c-GaN Mg is incorporated at different lattice sites or forms complexes. Si-doped c-GaN epilayers are n-type with electron concentrations up to 5*1019 cm-3. The incorporation of Si follows exactly the vapor pressure curve of Si, indicating a sticking coefficient of I for Si in c-GaN. With increasing Si-concentration the intensity of the near-band luminescence continuously increases and broadens.

Studies on Carbon as Alternative P-Type Dopant for Gallium Nitride

1998 ◽  
Vol 537 ◽  
Author(s):  
U. Birkle ◽  
M. Fehrer ◽  
V. Kirchner ◽  
S. Einfeldt ◽  
D. Hommel ◽  
...  
Keyword(s):  
Thermal Activation ◽  
Atomic Layer ◽  
Typical Feature ◽  
Acceptor Pair ◽  
Carbon Doped ◽  
Order Of Magnitude ◽  
Donor Acceptor ◽  
Donor Acceptor Pair ◽  
P Type ◽  
Carbon Concentrations

AbstractGaN layers were grown by molecular beam epitaxy and doped with carbon of nominal concentrations ranging from 1016 cm-1 to 10 20 cm-1. The incorporation of carbon leads to a reduction of the background electron concentration by one order of magnitude but the material remains n-type. For high carbon concentrations a re-increase of the carrier concentration is observed which is related to selfcompensation. Investigations of the donor-acceptor-pair luminescence show that doping with carbon is accompanied by the generation of a new donor exhibiting a thermal activation energy of about 55 meV. Layers grown by atomic layer epitaxy are marked by an increased intensity of the donor-acceptor-pair band luminescence which is attributed to the enforced incorporation of carbon onto the nitrogen sublattice. The yellow luminescence is found to be a typical feature of all carbon doped layers in contrast to nominally undoped samples.

Temperature Dependent Hall Measurements on CdGeAs2

1999 ◽  
Vol 607 ◽  
Author(s):  
A.J. Ptak ◽  
S. Jain ◽  
K.T Stevens ◽  
T.H. Myers ◽  
P.G. Schunemann ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Shallow Donor ◽  
Temperature Dependent ◽  
Out Of Plane ◽  
Background Doping ◽  
Apparent Variation ◽  
P Type ◽  
Matched Samples ◽  
Residual Growth

AbstractSeventeen samples of CdGeAs2 have been extensively characterized by temperature-dependent Hall effect and resistivity measurements. Due to the anisotropic nature of the electrical properties, carefully matched sample sets were fabricated with the c-axis either in or out of the plane of the sample. The matched samples allowed determination of carrier concentration and both in-plane and out-of-plane mobilities as a function of temperature. The electrical properties of both undoped and lightly doped samples were dominated by either native defects or residual growth impurities, leading to compensated p-type material. N-type doped material was obtained only with heavy doping. An apparent variation in acceptor activation energy between 110 and 165 meV could be best explained in terms of two deep acceptor levels and at least one shallow donor. Room temperature absorption coefficient data and the relation to background doping is also reported.

Electrical Properties and Defect Structures of CoO and MnO at High Defect Content

1985 ◽  
Vol 60 ◽  
Author(s):  
G.P. Sykora ◽  
T.O. Mason
Keyword(s):  
High Pressure ◽  
Electrical Properties ◽  
Point Defects ◽  
Defect Structures ◽  
Conduction Mechanisms ◽  
Pressure Oxygen ◽  
Defect Content ◽  
High Pressure Oxygen ◽  
Defect Interactions ◽  
P Type

AbstractDefect studies at high defect content in transition metal monoxides allow for the conduction mechanisms to be established and the nature of defect interactions to be studied. Conductivity and thermopower results in p-type, highly defective MnO are reported and analyzed with a combination of point defects and clusters. A high pressure oxygen apparatus to achieve defect contents up to 5 percent in CoO has been designed and constructed.

scholarly journals P- and N-Type Doping of MBE Grown Cubic GaN/GaAs Epilayers

1999 ◽  
Vol 4 (S1) ◽  
pp. 233-238
Author(s):  
D.J. As ◽  
T. Simonsmeier ◽  
J. Busch ◽  
B. Schöttker ◽  
M. Lübbers ◽  
...  
Keyword(s):  
Low Temperature ◽  
Shallow Donor ◽  
Rf Plasma ◽  
Pressure Curve ◽  
Blue Band ◽  
Vapor Pressure Curve ◽  
Cubic Gan ◽  
Donor Acceptor ◽  
Hall Effect Measurements ◽  
P Type

P-type doping with Mg and n-type doping with Si of cubic GaN (c-GaN) epilayers is reported. Cubic GaN films are grown by rf-plasma assisted MBE on semi-insulating GaAs (001) substrates at a substrate temperature of 720°C. Elemental Mg and Si are evaporated from thermal effusions cells. Secondary ion mass spectroscopy (SIMS), low temperature photoluminescence (PL) and temperature dependent Hall-effect measurements are used to study the incorporation, optical and electrical properties. A Mg related shallow donor-acceptor transiton at 3.04 eV with an acceptor activation energy of EA= 0.230 eV is observed by low temperature PL. At Mg concentrations above 1018 cm−3 the dominance of a broad blue band indicates that also in c-GaN Mg is incorporated at different lattice sites or forms complexes. Si-doped c-GaN epilayers are ntype with electron concentrations up to 5*1019 cm−3. The incorporation of Si follows exactly the vapor pressure curve of Si, indicating a sticking coefficient of 1 for Si in cGaN. With increasing Si-concentration the intensity of the near-band luminescence continuously increases and broadens.

p-doping of GaN by MOVPE

1997 ◽  
Vol 2 ◽  
Author(s):  
S. Haffouz ◽  
B. Beaumont ◽  
M. Leroux ◽  
M. Laugt ◽  
P. Lorenzini ◽  
...  
Keyword(s):  
Broad Band ◽  
Shallow Donor ◽  
Solid Particles ◽  
Activation Process ◽  
Ir Absorption ◽  
Local Vibration ◽  
Donor Acceptor ◽  
Si Doped ◽  
P Type ◽  
Mg Doped

Mg has been widely used as p-doping species despite its intrinsic difficulties. It is nowadays well established that during the growth process of Mg doped GaN, atomic H is generated from the decomposition of NH3 and Mg-H complexes are formed in the layer. This has been for instance shown by the occurrence of LO mode in IR absorption, and by the observation of the Mg-H local vibration modes. This H passivation limits the electrical activity of Mg, therefore an activation process is required to get full activation of the Mg atoms. In the present study, bismethylcyclopentadienyl magnesium [(MeCp)2Mg] was used as precursor. However, this precursor reacts in the gas phase with NH3 to produce tiny solid particles as evidenced by a very bright diffuse emission visible along the laser beam used for reflectometry measurements. This simplest obvious product would be [(MeCp)Mg(NH2)]m(m≥2). To limit this drawback, Ga and Mg precursor lines have been separated. With proper in situ heat treatment, doping densities up to 1.5×1018 cm−3 have been obtained. PL spectra of lightly Mg doped samples (1016 cm−3) are dominated by shallow donor-acceptor pairs whereas for higher doping densities ( 1018 cm−3), the luminescence is dominated by a broad band in the 2.7-2.9 eV range. GaN LEDs were fabricated from Si doped (n-type) and Mg-doped (p-type) GaN, these LEDs emit in the blue-UV range.

scholarly journals Analysis of the Visible and UV Electroluminescence in Homojunction GaN LED's

1998 ◽  
Vol 3 ◽  
Author(s):  
F. Calle ◽  
E. Monroy ◽  
F. J. Sánchez ◽  
E. Muñoz ◽  
B. Beaumont ◽  
...  
Keyword(s):  
Duty Cycle ◽  
Relaxation Times ◽  
Shallow Donor ◽  
Donor Acceptor ◽  
Level Model ◽  
High Bias ◽  
Shallow Acceptors ◽  
Current Characteristics ◽  
P Type

The electrical and electroluminescent properties of MOVPE GaN p-n homojunctions have been analyzed as a function of temperature and bias. Electroluminescence is observed for V>3 V under dc and ac conditions. The main emission at low T is a donor-acceptor transition involving shallow acceptors, though it disappears at higher T due to the ionization of the acceptors and compensation by ionized donors. Room temperature dc and ac electroluminescence spectra evolve under increasing bias from a blue-shifting visible band involving deep states at the p-type side of the p-n junction, to a band-to-band UV recombination at high bias. In agreement, the superlinear dependence of light-current characteristics at low current injection becomes linear when the defects are saturated. Time analysis of the spectra vs pulse duration and duty cycle allows the determination of the visible radiative recombination and relaxation times associated to the Mg-related deep states, which are found to behave as acceptors lying 0.55 eV above the valence band. A simple 3-level model is able to explain the visible emission, which involves the conduction band (or shallow donor) and those deep acceptors in the p-layer. Optimum UV/visible ratio emission requires intense and relatively long pulses, with a high duty cycle to impede visible recombination.

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