Size dependence effective band gap in GaSb nano-solid

2013 ◽  
Author(s):  
Bhoopendra Dhar Diwan ◽  
Vinod Kumar Dubey
Keyword(s):  
Band Gap ◽  
Size Dependence

Mechanism for Size Dependence of Light Emission From ZnO Nanocrystallites

2007 ◽  
Author(s):  
Fuli Zhao ◽  
Xiaofang Wang ◽  
Pingbo Xie ◽  
Ningsheng Xu ◽  
Zhizhan Xu
Keyword(s):  
Band Gap ◽  
Zno Nanoparticles ◽  
Size Dependence ◽  
Laser Excitation ◽  
Light Emission ◽  
Surface States ◽  
Picosecond Laser ◽  
One Dimensional ◽  
1D Model ◽  
Critical Grain Size

Broadband light emission of different sized ZnO nanoparticles (17 nm to 300 nm) has been measured under picosecond laser excitation. Each spectrum consists of three Gaussian components including one emerging inside band-gap. Such inside band-gap band shows a clear dependence of the weighted intensity on the sizes of nanoparticles. Originated from our simplified one-dimensional (1D) model it has been qualitatively deduced that such size dependence match with the surface-state modified band structure. Additionally, a critical grain size as 110 nm for surface states recombination of ZnO nanoparticles has been found experimentally.

Semiconductor Pb2P2S6 and size-dependent band gap energy of its nanoparticles

RSC Advances ◽  
2014 ◽  
Vol 4 (65) ◽  
pp. 34288-34293 ◽  
Author(s):  
Xian Zhang ◽  
Jianqiao He ◽  
Wei Chen ◽  
Chao Wang ◽  
Chong Zheng ◽  
...  
Keyword(s):  
Optical Properties ◽  
Band Gap ◽  
Ball Milling ◽  
High Speed ◽  
Size Dependence ◽  
Band Gap Energy ◽  
Gap Energy ◽  
Size Dependent ◽  
Ball Milling Technique ◽  
High Speed Ball Milling

Microcrystalline Pb2P2S6 powder was synthesized via a traditional melting salt method. The nanostructured Pb2P2S6 powder was further synthesized by a high-speed ball milling technique. The optical properties of the Pb2P2S6 powder show a size-dependence, with the band gap ranging from 2.56 eV to 2.88).

Size Dependence of Radiative Rates in the Indirect Band Gap Material AgBr

1994 ◽  
Vol 116 (4) ◽  
pp. 1585-1586 ◽  
Author(s):  
Wei Chen ◽  
George McLendon ◽  
Alfred Marchetti ◽  
Julie M. Rehm ◽  
Michal Ilana Freedhoff ◽  
...  
Keyword(s):  
Band Gap ◽  
Size Dependence ◽  
Indirect Band Gap

Excitonic Contribution of Nanosilicon on Light Emitting Properties

2011 ◽  
Vol 364 ◽  
pp. 308-312
Author(s):  
Sib Krishna Ghoshal ◽  
M.R. Sahar ◽  
M. Supar Rohani
Keyword(s):  
Band Gap ◽  
Electronic Properties ◽  
Size Dependence ◽  
Optical Band Gap ◽  
Surface States ◽  
Light Emitting ◽  
Optical And Electronic Properties ◽  
Pl Intensity ◽  
Excitonic Effects ◽  
Si Quantum Dots

A phenomenological model is developed by integrating the effect of excitonic energy states, localized surface states and quantum confinement (QC) to obtain an analytical expression for the room temperature photoluminescence (PL) intensity. We calculate the binding energy of strongly confined excitons in silicon (Si) quantum dots (QD) having sizes 1 to 7.75 nm to examine its contribution on optical band gap and electronic properties. The band gap with excitonic contribution is found to decrease as much as 0.23 eV for the smallest dot. The effect of exciton states explains almost accurately the experimental PL data. Our model provides the mechanism for controlling the PL intensity through fitting parameters. Huge excitonic effects, which depend strongly on QD size and shape, characterize the optical spectra. The results for the size dependence of the optical band gap, the PL intensity, and oscillator strength are presented the role excitonic effects on optical and electronic properties are discussed.

Molecular Limit of a Bulk Semiconductor:  Size Dependence of the “Band Gap” in CdSe Cluster Molecules

2000 ◽  
Vol 122 (11) ◽  
pp. 2673-2674 ◽  
Author(s):  
V. N. Soloviev ◽  
A. Eichhöfer ◽  
D. Fenske ◽  
U. Banin
Keyword(s):  
Band Gap ◽  
Size Dependence ◽  
Bulk Semiconductor

TEM and cathodoluminescence of precipitates in II-VI semiconductors

1988 ◽  
Vol 46 ◽  
pp. 488-489
Author(s):  
Joanna L. Batstone
Keyword(s):  
Crystal Growth ◽  
Band Gap ◽  
Local Strain ◽  
Wide Band ◽  
Optoelectronic Device ◽  
Wide Band Gap ◽  
Bulk Crystal Growth ◽  
Transmission Electron ◽  
Device Applications ◽  
Stoichiometry Control

Interest in II-VI semiconductors centres around optoelectronic device applications. The wide band gap II-VI semiconductors such as ZnS, ZnSe and ZnTe have been used in lasers and electroluminescent displays yielding room temperature blue luminescence. The narrow gap II-VI semiconductors such as CdTe and HgxCd1-x Te are currently used for infrared detectors, where the band gap can be varied continuously by changing the alloy composition x.Two major sources of precipitation can be identified in II-VI materials; (i) dopant introduction leading to local variations in concentration and subsequent precipitation and (ii) Te precipitation in ZnTe, CdTe and HgCdTe due to native point defects which arise from problems associated with stoichiometry control during crystal growth. Precipitation is observed in both bulk crystal growth and epitaxial growth and is frequently associated with segregation and precipitation at dislocations and grain boundaries. Precipitation has been observed using transmission electron microscopy (TEM) which is sensitive to local strain fields around inclusions.

Structural properties of GaAs/InGaAs/GaAs (001) and InGaAs/GaAs (001) heterostructures and correlation with electronic properties

1990 ◽  
Vol 48 (4) ◽  
pp. 602-603
Author(s):  
J.M. Bonar ◽  
R. Hull ◽  
R. Malik ◽  
R. Ryan ◽  
J.F. Walker
Keyword(s):  
Band Gap ◽  
Electronic Properties ◽  
Gaas Substrate ◽  
Critical Thickness ◽  
Lattice Mismatch ◽  
Band Offset ◽  
Misfit Dislocations ◽  
Gaas Substrates ◽  
Gaas Structure ◽  
Low X

In this study we have examined a series of strained heteropeitaxial GaAs/InGaAs/GaAs and InGaAs/GaAs structures, both on (001) GaAs substrates. These heterostructures are potentially very interesting from a device standpoint because of improved band gap properties (InAs has a much smaller band gap than GaAs so there is a large band offset at the InGaAs/GaAs interface), and because of the much higher mobility of InAs. However, there is a 7.2% lattice mismatch between InAs and GaAs, so an InxGa1-xAs layer in a GaAs structure with even relatively low x will have a large amount of strain, and misfit dislocations are expected to form above some critical thickness. We attempt here to correlate the effect of misfit dislocations on the electronic properties of this material.The samples we examined consisted of 200Å InxGa1-xAs layered in a hetero-junction bipolar transistor (HBT) structure (InxGa1-xAs on top of a (001) GaAs buffer, followed by more GaAs, then a layer of AlGaAs and a GaAs cap), and a series consisting of a 200Å layer of InxGa1-xAs on a (001) GaAs substrate.

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