scholarly journals Time Resolved Photoluminescence of Cubic Mg Doped GaN

1999 ◽  
Vol 572 ◽  
Author(s):  
R. Seitz ◽  
C. Gaspar ◽  
T. Monteiro ◽  
E. Pereira ◽  
B. Schoettker ◽  
...  
Keyword(s):  
Blue Emission ◽  
Spectral Shift ◽  
Excitation Density ◽  
Acceptor Pair ◽  
Time Resolved ◽  
Deep Donor ◽  
Cubic Gan ◽  
Donor Acceptor ◽  
Time Resolved Photoluminescence ◽  
Mg Doped

ABSTRACTMg doped cubic GaN layers were studied by steady state and time resolved photoluminescence. The blue emission due to Mg doping can be decomposed in three bands. The decay curves and the spectral shift with time delays indicates donor-acceptor pair behaviour. This can be confirmed by excitation density dependent measurements. Furthermore temperature dependent analysis shows that the three emissions have one impurity in common. We propose that this is an acceptor level related to the Mg incorporation and the three deep donor levels are due to compensation effects.

scholarly journals On the origin of the 2.8 eV blue emission in p-type GaN:Mg : A time-resolved photoluminescence investigation

2001 ◽  
Vol 6 ◽  
Author(s):  
F. Shahedipour ◽  
B.W. Wessels
Keyword(s):  
Luminescence Intensity ◽  
Random Distribution ◽  
Blue Emission ◽  
Acceptor Pair ◽  
Time Resolved ◽  
Donor Acceptor ◽  
Shallow Acceptors ◽  
Donor Acceptor Pair ◽  
P Type ◽  
Time Resolved Photoluminescence

The decay dynamics of the 2.8 eV emission band in p-type GaN was investigated using time-resolved photoluminescence spectroscopy. The luminescence intensity decays non-exponentially. The decay dynamics were consistent with donor-acceptor pair recombination for a random distribution of pair distances. Calculations using the Thomas-Hopfield model indicated that recombination involves deep donors and shallow acceptors.

Deep Donor-Acceptor Pair Luminescence in Codoped GaN

2002 ◽  
Vol 743 ◽  
Author(s):  
Bing Han ◽  
Joel M. Gregie ◽  
Melville P. Ulmer ◽  
Bruce W. Wessels
Keyword(s):  
Luminescence Band ◽  
Room Temperature ◽  
Deep Level ◽  
Excitation Density ◽  
Acceptor Pair ◽  
Deep Donor ◽  
Donor Acceptor ◽  
Donor Acceptor Pair ◽  
Increasing Temperature ◽  
Luminescent Behavior

ABSTRACTDeep level defects formed in p-type GaN:Mg codoped with shallow donors have been investigated by photoluminescence (PL) spectroscopy. A donor-acceptor pair (DAP) luminescence band peaked at 2.45 eV dominates the room temperature PL spectrum in heavily codoped epilayers. A superlinear dependence of PL intensity on excitation density is observed for this band, with an exponent of 1.4∼1.7. The intensity of this band increases with increasing temperature with a maximum at 264K. To explain the luminescent behavior a DAP model was developed whereby the recombination involves a deep donor and shallow Mg acceptor. The deep donor is tentatively attributed to a DX center.

HOW DO WE LOSE EXCITATION IN THE GREEN?

2011 ◽  
Vol 20 (01) ◽  
pp. 13-25 ◽  
Author(s):  
CHRISTIAN WETZEL ◽  
YONG XIA ◽  
WEI ZHAO ◽  
YUFENG LI ◽  
MINGWEI ZHU ◽  
...  
Keyword(s):  
Structural Defects ◽  
Excitation Density ◽  
Acceptor Pair ◽  
Time Resolved ◽  
High Brightness ◽  
Light Emitting ◽  
Homoepitaxial Growth ◽  
Bulk Gan ◽  
Donor Acceptor ◽  
Crystallographic Axes

Efficiency droop and green gap are terms that summarize performance limitations in GaInN / GaN high brightness light emitting diodes (LEDs). Here we summarize progress in the development of green LEDs and report on time resolved luminescence data of polar c -plane and non-polar m -plane material. We find that by rigorous reduction of structural defects in homoepitaxy on bulk GaN and V -defect suppression, higher efficiency at longer wavelengths becomes possible. We observe that the presence of donor acceptor pair recombination within the active region correlates with lower device performance. To evaluate the aspects of piezoelectric polarization we compare LED structures grown along polar and non-polar crystallographic axes. In contrast to the polar material we find single exponential luminescence decay and emission wavelengths that remain stable irrespective of the excitation density. Those findings render high prospects for overcoming green gap and droop in non-polar homoepitaxial growth.

scholarly journals Identification of a Cubic Phase in Epitaxial Layers of Predominantly Hexagonal GaN

1996 ◽  
Vol 1 ◽  
Author(s):  
U. Strauss ◽  
H. Tews ◽  
H. Riechert ◽  
R. Averbeck ◽  
M. Schienle ◽  
...  
Keyword(s):  
Continuous Wave ◽  
Cubic Phase ◽  
Epitaxial Layers ◽  
X Ray Diffraction ◽  
Acceptor Pair ◽  
Time Resolved ◽  
Probing Depth ◽  
Decay Times ◽  
Cubic Gan ◽  
Donor Acceptor

Epitaxial layers of GaN on c-plane sapphire are analyzed by continuous-wave and time-resolved photoluminescence at 4K and by X-ray diffraction. Besides the well-known emissions from hexagonal GaN we observe luminescence bands at 3.279 and 3.15 to 3.21 eV which are identified as the transition of the donor bound exciton and the donor-acceptor pair recombination in cubic GaN, respectively. Measurements of the luminescence decay times are essential for the clarification of the emission processes. Due to the probing depth of about 200 nm in PL we find that the fraction of cubic phase typically decreases with layer thickness. In our best samples, however, we do not detect the cubic phase at all.

Time Resolved Photoluminescence Spectroscopy on GaN Epitaxial Layers

1995 ◽  
Vol 378 ◽  
Author(s):  
B. K. Meyer ◽  
D. Volm ◽  
C. Wetzel ◽  
L. Eckey ◽  
J.-Ch. Holst ◽  
...  
Keyword(s):  
Low Temperatures ◽  
Photoluminescence Spectroscopy ◽  
Epitaxial Layers ◽  
Acceptor Pair ◽  
Time Resolved ◽  
Sapphire Substrates ◽  
Donor Acceptor ◽  
Donor Acceptor Pair ◽  
Time Resolved Photoluminescence

AbstractFree and bound exciton luminescences as well as donor-acceptor pair recombination of GaN epitaxial layers on 6H-SiC and sapphire substrates were investigated using time integrated and time resolved photoluminescence measurements at low temperatures. Lifetimes are determined for the donor bound exciton at 3.4722eV and for two acceptor bound excitons with energies of 3.4672eV and 3.459eV. Luminescences between 3.29eV and 3.37eV are identified as due to excitons deeply bound to centers located near the substrate-epilayer interface.

Defects in bulk ZnO studied by steady-state and time-resolved photoluminescence

2007 ◽  
Vol 1035 ◽  
Author(s):  
Michael A. Reshchikov
Keyword(s):  
Broad Band ◽  
Peak Position ◽  
Pulse Excitation ◽  
Time Interval ◽  
Acceptor Pair ◽  
Time Resolved ◽  
Nonexponential Decay ◽  
Donor Acceptor ◽  
Pl Spectrum ◽  
Time Resolved Photoluminescence

AbstractUnintentionally doped bulk ZnO samples were grown by hydrothermal method in Tokyo Denpa Co. Ltd. (Japan) and MTI Corporation. At low temperatures the PL spectrum contained a very broad band with the peak position (between 2.0 and 2.4 eV) depending on the excitation intensity. Evolution of the PL spectrum after a pulse excitation revealed that the broad band is composed of an orange (OL) and green (GL) luminescence bands having maxima at 1.96 and ∼2.35 eV, respectively. The GL band dominated at times up to 1 ms and then disappeared. The OL band decayed as approximately t−1 over a wide time interval, and its spectrum could be recorded even 24 hours after the excitation source was switched off. The slow nonexponential decay of the OL band is attributed to transitions from shallow donors to a deep acceptor (donor-acceptor pair transitions).

scholarly journals Time-resolved Spectroscopy of the violet luminescence of undoped AlN

2005 ◽  
Vol 10 ◽  
Author(s):  
R. Freitag ◽  
K. Thonke ◽  
R. Sauer ◽  
D. G. Ebling ◽  
L. Steinke
Keyword(s):  
Epitaxial Layers ◽  
Yellow Luminescence ◽  
Acceptor Pair ◽  
Time Resolved ◽  
Time Resolved Spectroscopy ◽  
Violet Luminescence ◽  
Donor Acceptor ◽  
Violet Band ◽  
Donor Acceptor Pair

We report on the time-resolved luminescence of the defect-related violet band from undoped AlN epitaxial layers grown on sapphire and SiC. For both measurements in photoluminescence and in cathodoluminescence a decay of algebraic nature at long times is observed. This is typical for donor-acceptor pair transitions. We compare the behavior of this band to that of the generically yellow luminescence of GaN.

Mechanism of donor–acceptor pair recombination in Mg-doped GaN epilayers grown on sapphire substrates

1998 ◽  
Vol 84 (4) ◽  
pp. 2082-2085 ◽  
Author(s):  
T. W. Kang ◽  
S. H. Park ◽  
H. Song ◽  
T. W. Kim ◽  
G. S. Yoon ◽  
...  
Keyword(s):  
Acceptor Pair ◽  
Sapphire Substrates ◽  
Donor Acceptor ◽  
Donor Acceptor Pair ◽  
Mg Doped
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