Electron Accumulation in AIGaSb/InAs Qw System, - Evidence for Coexistence of Deep Acceptor and Donor -

ABSTRACTWe investigated the reason of the (imbalanced) accumulation of electrons in AIGaSb/lnAs/AIGaSb QW system in spite of the p-type conduction of undoped AIGaSb. It was found that the concentration of the accumulated electrons negligibly depended on the number of the interfaces, but increased linearly with the effective AlSb thickness. These results indicate that donor levels in AIGaSb are the dominant electron sources. We propose a model that the deep acceptors with larger concentration and donors coexist, and the electron accumulation depends on the energy position of the acceptor in AIGaSb with respect to the quantum level in the InAs well. Acceptor levels obtained experimentally are about 100 meV higher than the bottom of the InAs conduction band, and we succeeded in eliminating the electron accumulation by making the quantum level of the InAs well higher than this acceptor level. The origins of the donors and acceptors are also discussed.

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Progress in ZnO Acceptor Doping: What Is the Best Strategy?

Advances in Condensed Matter Physics ◽

10.1155/2014/457058 ◽

2014 ◽

Vol 2014 ◽

pp. 1-15 ◽

Cited By ~ 23

Author(s):

Judith G. Reynolds ◽

C. Lewis Reynolds

Keyword(s):

Theoretical Calculations ◽

Acceptor Doping ◽

Deep Acceptor ◽

Defect Complexes ◽

Impurity Species ◽

Dopant Impurity ◽

P Type ◽

Type Conduction ◽

Oxygen Site ◽

Zinc Site

This paper reviews the recent progress in acceptor doping of ZnO that has been achieved with a focus toward the optimum strategy. There are three main approaches for generating p-type ZnO: substitutional group IA elements on a zinc site, codoping of donors and acceptors, and substitution of group VA elements on an oxygen site. The relevant issues are whether there is sufficient incorporation of the appropriate dopant impurity species, does it reside on the appropriate lattice site, and lastly whether the acceptor ionization energy is sufficiently small to enable significant p-type conduction at room temperature. The potential of nitrogen doping and formation of the appropriate acceptor complexes is highlighted although theoretical calculations predict that nitrogen on an oxygen site is a deep acceptor. We show that an understanding of the growth and annealing steps to achieve the relevant acceptor defect complexes is crucial to meet requirements.

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Built-in Potential and Open Circuit Voltage of Heterojunction CuIn1-xGaxSe2 Solar Cells

MRS Proceedings ◽

10.1557/proc-865-f5.19 ◽

2005 ◽

Vol 865 ◽

Cited By ~ 5

Author(s):

Akimasa Yamada ◽

Koji Matsubara ◽

Keiichiro Sakurai ◽

Shogo Ishizuka ◽

Hitoshi Tampo Hajime ◽

...

Keyword(s):

Solar Cells ◽

Conduction Band ◽

Fermi Energy ◽

Open Circuit Voltage ◽

Material Selection ◽

Open Circuit ◽

Flat Band ◽

Band Energy ◽

Low X ◽

P Type

AbstractThe reasons why the open circuit voltage (Voc) of high-x CuIn1-xGaxSe2 (CIGS)/ZnO solar cells remain low are discussed. Here it is shown that the Voc ceiling can be interpreted simply on the basis of a model that the valence-band energy (Ev) of CIGS is almost immovable irrespective of x. When the conduction-band energy (Ec) of ZnO is lower than that of high-x CIGS (DEc<0), the built-in potential (Vbi) of a CIGS/ZnO junction is equivalent to the flat-band potential (Vbi) that arises from the separation between the Fermi energies of the two materials. If the Ev (and therefore the Fermi energy) of p-type CIGS is constant with increasing x, the Vbi and Voc that follows the Vbi remain unchanged since the Fermi energy of ZnO is constant. This unchangeable Voc reduces the conversion efficiency of high-x CIGS cells in cooperation with reduced photocurrents due to a larger bandgap. A positive offset, ΔEc>o gives rise to a photoelectrons barrier in the conduction-band that partially cancels Voc, thus the Voc of a low-x CIGS cell is governed by the Ec of CIGS. Based upon this concept, a material selection guideline is given for the windows and transparent electrodes appropriate for high-x CIGS absorbers-based solar cells.

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Atomic nitrogen doping and p-type conduction in SnO2

Applied Physics Letters ◽

10.1063/1.3258354 ◽

2009 ◽

Vol 95 (22) ◽

pp. 222112 ◽

Cited By ~ 68

Author(s):

S. S. Pan ◽

G. H. Li ◽

L. B. Wang ◽

Y. D. Shen ◽

Y. Wang ◽

...

Keyword(s):

Nitrogen Doping ◽

Atomic Nitrogen ◽

P Type ◽

Type Conduction

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Deep Acceptor Level in Heat Treated Indium Antimonide

physica status solidi (b) ◽

10.1002/pssb.19690330263 ◽

1969 ◽

Vol 33 (2) ◽

pp. K129-K132 ◽

Cited By ~ 4

Author(s):

P. Kordoš

Keyword(s):

Indium Antimonide ◽

Acceptor Level ◽

Deep Acceptor ◽

Heat Treated ◽

Deep Acceptor Level

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Laser-Doped SiC as Wireless Remote Gas Sensor Based on Semiconductor Optics

Materials Science Forum ◽

10.4028/www.scientific.net/msf.717-720.1195 ◽

2012 ◽

Vol 717-720 ◽

pp. 1195-1198

Author(s):

Geunsik Lim ◽

Tariq Manzur ◽

Aravinda Kar

Keyword(s):

Valence Band ◽

Energy Gap ◽

Gas Sensing ◽

Optical Signal ◽

Acceptor Level ◽

Spectral Bands ◽

Sensing Applications ◽

Electro Optic ◽

Midwave Infrared ◽

P Type

An uncooled SiC-based electro-optic device is developed for gas sensing applications. P-type dopants Ga, Sc, P and Al are incorporated into an n-type crystalline 6H-SiC substrate by a laser doping technique for sensing CO2, CO, NO2 and NO gases, respectively. Each dopant creates an acceptor energy level within the bandgap of the substrate so that the energy gap between this acceptor level and the valence band matches the quantum of energy emitted by the gas of interest. The photons of the gas excite electrons from the valence band to the acceptor level, which alters the electron density in these two states. Consequently, the refractive index of the substrate changes, which, in turn, modifies the reflectivity of the substrate. This change in reflectivity represents the optical signal of the sensor, which is probed remotely with a laser such as a helium-neon laser. Although the midwave infrared (3-5 mm) band is studied in this paper, the approach is applicable to other spectral bands.

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Solution-phase synthesized iron telluride nanostructures with controllable thermally triggered p-type to n-type transition

Nanoscale ◽

10.1039/c8nr06418k ◽

2018 ◽

Vol 10 (44) ◽

pp. 20664-20670

Author(s):

Wei Zheng ◽

Sungbum Hong ◽

Bokki Min ◽

Yue Wu

Keyword(s):

Solution Phase ◽

Switching Behavior ◽

Phase Synthesis ◽

Type Transition ◽

Solution Phase Synthesis ◽

Iron Telluride ◽

P Type ◽

Thermally Triggered ◽

Type Conduction

We report the solution-phase synthesis of iron telluride with controllable reversible switching behavior between p- and n-type conduction.

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Properties of 4H-SiC by Sublimation Close Space Technique

MRS Proceedings ◽

10.1557/proc-572-179 ◽

1999 ◽

Vol 572 ◽

Author(s):

S. Nishino ◽

K. Matsumoto ◽

Y. Chen ◽

Y. Nishio

Keyword(s):

Schottky Diode ◽

Source Material ◽

Epitaxial Layers ◽

Power Devices ◽

High Quality ◽

Substrate Quality ◽

Space Technique ◽

P Type ◽

Type Conduction

ABSTRACTSiC is suitable for power devices but high quality SiC epitaxial layers having a high breakdown voltage are needed and thick epilayer is indispensable. In this study, CST method (Close Space Technique) was used to rapidly grow thick epitaxial layers. Source material used was 3C-SiC polycrystalline plate of high purity while 4H-SiC(0001) crystals inclined 8° off toward <1120> was used for the substrate. Quality of the epilayer was influenced significantly by pressure during growth and polarity of the substrate. A p-type conduction was obtained by changing the size of p-type source material. The carrier concentration of epilayer decreased when a lower pressure was employed. Schottky diode was also fabricated.

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The role of the VZn–NO–H complex in the p-type conductivity in ZnO

Physical Chemistry Chemical Physics ◽

10.1039/c4cp05894a ◽

2015 ◽

Vol 17 (7) ◽

pp. 5485-5489 ◽

Cited By ~ 13

Author(s):

M. N. Amini ◽

R. Saniz ◽

D. Lamoen ◽

B. Partoens

Keyword(s):

First Principles ◽

Formation Energy ◽

First Principles Calculations ◽

Deep Acceptor ◽

Type Conductivity ◽

Acceptor Complex ◽

Hole Level ◽

P Type

With the help of first-principles calculations, we investigate the VZn–NO–H acceptor complex in ZnO. We find that H plays an important role, because it lowers the formation energy of the complex with respect to VZn–NO, a complex known to exhibit p-type behavior. However, this additional H atom also occupies the hole level of VZn–NO making the VZn–NO–H complex a deep acceptor.

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