Resonant Excitation Spectroscopy of Light-Emitting Silicon Nanostructures

1997 ◽  
Vol 486 ◽  
Author(s):  
Yoshihiko Kanemitsu ◽  
Shinji Okamoto
Keyword(s):  
Quantum Wells ◽  
Electronic Structures ◽  
Resonant Excitation ◽  
Luminescence Properties ◽  
Luminescence Spectra ◽  
Light Emitting ◽  
Si Nanocrystals ◽  
Crystalline Nature ◽  
Si Nanostructures ◽  
Excited Luminescence

AbstractWe have studied optical properties and electronic structures of zero-dimensional (OD) Si nanocrystals and two-dimensional (2D) Si quantum wells by means of resonant excitation spectroscopy. Resonantly excited luminescence spectra of 0D Si nanocrystals are sensitive to the surface structure. The size dependence of the photoluminescence (PL) properties and resonantly excited PL spectra of SiO2-capped Si nanocrystals indicate that excitons are localized at the interface between the c-Si and SiO2 surface layer. The TO-phonon related structure in resonantly excited luminescence is clearly observed in H-passivated Si nanocrystals. Hpassivated Si nanocrystals show their crystalline nature, while the oxidized Si nanocrystals show their disordered nature. Luminescence properties of Si/SiO2 nanocrystals are similar to those of Si/SiO2 quantum wells. The electronic structures and luminescence properties of Si nanostructures are discussed.

The Emission Properties of Light Emitting Diodes using InGaN/AlGaN/GaN Multiple Quantum Wells

1998 ◽  
Vol 3 ◽  
Author(s):  
A. E. Yunovich ◽  
V. E. Kudryashov ◽  
A. N. Turkin ◽  
A. Kovalev ◽  
F. Manyakhin
Keyword(s):  
Quantum Wells ◽  
Quantum Efficiency ◽  
Light Emitting Diodes ◽  
Multiple Quantum Wells ◽  
Luminescence Spectra ◽  
Multiple Quantum ◽  
Tunnel Current ◽  
High Quantum Efficiency ◽  
Light Emitting ◽  
Low Probability

Luminescence spectra of Light Emitting Diodes (LEDs) with Multiple Quantum Wells (MQWs) were studied at currents J = 0.15 μA - 150 mA. A high quantum efficiency at low J is caused by a low probability of the tunnel current J (which is maximum at Jm ≈ 0.5-1.0 mA). J(V) curves were measured in the range J= 10−12-10−1 A; at J > 10−3A they may be approximated by a sum of four parts: V= φk+ mkT·[ln(J/J0)+(J/J1)0.5] + J·Rs. The part V ~ (J/J1)0.5is the evidence of a double-injection into i-layers near MQWs. Their presence is confirmed by capacitance measurements. An overflow of carriers through the MQW causes a lower quantum efficiency at high J. A model of a 2D-density of states with exponential tails fits the spectra. The value of T in the active layer was estimated. A new band was detected at high J; it can be caused by non-uniformity of In content in MQWs.

Efficient green phosphor realized by Ce3+→Tb3+ energy transfer in Li3Sc2(PO4)3 for ultraviolet white light-emitting diodes

2018 ◽  
Vol 20 (42) ◽  
pp. 26995-27002 ◽  
Author(s):  
Mengmeng Jiao ◽  
Qinfeng Xu ◽  
Mingliang Liu ◽  
Chuanlu Yang ◽  
Yongjiang Yu
Keyword(s):  
Energy Transfer ◽  
White Light ◽  
Electronic Structures ◽  
Light Emitting Diodes ◽  
Luminescence Properties ◽  
Green Phosphor ◽  
Light Emitting ◽  
White Light Emitting Diodes

UV excited green-emitting Li3Sc2(PO4)3:Ce3+,Tb3+ phosphors have been obtained, and their electronic structures and luminescence properties have been investigated in detail.

Luminescence spectra of blue and green light-emitting diodes based on multilayer InGaN/AlGaN/GaN heterostructures with quantum wells

1997 ◽  
Vol 31 (9) ◽  
pp. 901-907 ◽  
Author(s):  
K. G. Zolina ◽  
V. E. Kudryashov ◽  
A. N. Turkin ◽  
A. É. Yunovich
Keyword(s):  
Quantum Wells ◽  
Light Emitting Diodes ◽  
Green Light ◽  
Luminescence Spectra ◽  
Light Emitting

Luminescence properties of Na3LuSi3O9:Ce3+ as a potential scintillator material

RSC Advances ◽  
2015 ◽  
Vol 5 (124) ◽  
pp. 102477-102480 ◽  
Author(s):  
Jianbang Zhou ◽  
Fengjuan Pan ◽  
Jiuping Zhong ◽  
Hongbin Liang ◽  
Qiang Su ◽  
...  
Keyword(s):  
Luminescence Properties ◽  
Luminescence Spectra ◽  
X Ray ◽  
Scintillator Material ◽  
Excited Luminescence

Comparison between the X-ray excited luminescence spectra of the Bi4Ge3O12 (BGO) and Na3Lu0.99Ce0.01Si3O9 powders.

Activation of Lead Fluoride Room Temperature Luminescence by Structural Modifications

1994 ◽  
Vol 348 ◽  
Author(s):  
D.L. Alov ◽  
A.V. Bazhenov ◽  
V.K. Egorov ◽  
G.A. Emelchenko ◽  
N.V. Klassen ◽  
...  
Keyword(s):  
Room Temperature ◽  
Structural Characteristics ◽  
Structural Defects ◽  
Luminescence Spectra ◽  
Lead Fluoride ◽  
Light Emitting ◽  
X Ray ◽  
Structural Modifications ◽  
Excited Luminescence ◽  
Room Temperature Luminescence

ABSTRACTThe connection of lead fluoride luminescence properties with its structural characteristics has been studied. Single crystals of the cubic and orthorombic phases, cubic and orthorombic powders, pressure compacted orthorombic ceramics, plastically deformed crystals were used. The photo- and X-ray excited luminescence spectra have been investigated. The experimental results have shown that the room temperature luminescence of lead fluoride can be accounted for local light emitting centers which are produced by the intrinsic structural defects in the orthorombic lead fluoride.

scholarly journals Aging Mechanisms of InGaN/AlGaN/GaN Light-Emitting Diodes Operating at High Currents

1998 ◽  
Vol 3 ◽  
Author(s):  
F. Manyakhin ◽  
A. Kovalev ◽  
A. E. Yunovich
Keyword(s):  
Quantum Wells ◽  
Light Emitting Diodes ◽  
Defect Formation ◽  
Hot Electrons ◽  
Luminescence Spectra ◽  
Single Quantum ◽  
Light Emitting ◽  
Long Period ◽  
Aging Mechanisms ◽  
Two Stages

Changes of luminescence spectra and electrical properties of light-emitting diodes (LED’s) based on InGaN/AlGaN/GaN heterostructures were investigated over a long period of operation. Blue and green LED’s with InGaN single quantum wells were studied at currents up to 80 mA for 102−2.103 hours. An increase of luminescence intensity at operating currents of 15 mA was detected at the 1st stage of aging (100−800 hours) and a slow fall was detected in the 2nd stage. Greater changes of spectra were observed at low currents (< 0.15 mA). A study of charged acceptor distribution in the space charge region has shown that at the 1st stage their concentration grows, and in the 2nd stage, it falls. The models for the two stages are proposed: 1) activation of Mg due to destruction of residual Mg-H complexes; 2) formation of donor vacancies N. A model of defect formation by hot electrons injected into the quantum well is discussed.

Electrical Properties and Luminescence Spectra of Light-Emitting Diodes with Modulated Doped InGaN/GaN Quantum Wells

2002 ◽  
Vol 722 ◽  
Author(s):  
A.E. Yunovich ◽  
S.S. Mamakin ◽  
M.V. Lomonosov ◽  
F.I. Manyakhin ◽  
A.B. Wattana ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Light Emitting Diodes ◽  
Debye Length ◽  
Green Light ◽  
Luminescence Spectra ◽  
Multiple Quantum ◽  
Energy Diagram ◽  
Light Emitting ◽  
Charge Distributions ◽  
Piezoelectric Fields

AbstractCharge distributions N(z) and electroluminescence spectra of blue and green light-emitting diodes (LEDs) based on InGaN/AlGaN/GaN heterostructures with multiple quantum wells. MQWs were modulated doped by Si donors in GaN barriers, electrons from donors being in InGaN wells. N(z) were determined using dynamical capacitance (C-V) method. Acceptor and donor concentrations near the p-n- junction were approximately NA ≥1.1019 cm-3 >> ND ≥ 1.1018 cm-3. Functions N(z) have periodic maxima and minima; their number was 4 and a period of 10 %15 nm, according to the details of growth. The extrema reflect charge distributions in MQWs on the n-side of the junctions with accuracy in z of the order of the Debye length (2-3 nm). An energy diagram of the structures is calculated according these measurements. Shifts of spectral maxima with current (J = 10-6 – 3.10-2 A) for these LEDs are comparatively low (3-12 meV for blue LEDs and 20-50 meV for green ones), much less than for previously studied green LEDs (up to 150 meV). This behavior is explained by screening of piezoelectric fields by electrons in the wells. Quantum efficiency versus current is correlated with N(z) distributions and currentvoltage characteristics of the LEDs.

Sign in / Sign up

Export Citation Format

Share Document