Spatially resolved photoluminescence in InGaN/GaN quantum wells by near-field scanning optical microscopy

2001 ◽  
Vol 79 (7) ◽  
pp. 976-978 ◽  
Author(s):  
M. S. Jeong ◽  
J. Y. Kim ◽  
Y.-W. Kim ◽  
J. O. White ◽  
E.-K. Suh ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Optical Microscopy ◽  
Near Field ◽  
Spatially Resolved ◽  
Scanning Optical Microscopy ◽  
Near Field Scanning

scholarly journals Nanoscale Characterization of V-defect in InGaN/GaN QWs LEDs using Near-Field Scanning Optical Microscopy

Nanomaterials ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 633 ◽  
Author(s):  
Li ◽  
Tang ◽  
Zhang ◽  
Guo ◽  
Li ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Optical Microscopy ◽  
Quantum Efficiency ◽  
External Quantum Efficiency ◽  
Near Field ◽  
Light Output ◽  
Current Injection ◽  
Light Output Power ◽  
Scanning Optical Microscopy ◽  
Near Field Scanning

The size of the V-defects in the GaN/InGaN-based quantum wells blue light-emitting diode (LED) was intentionally modified from 50 nm to 300 nm. High resolution photoluminescence and electroluminescence of a single large V-defect were investigated by near-field scanning optical microscopy. The current distribution along the {10-11} facets of the large defect was measured by conductive atomic force microscopy. Nearly 20 times the current injection and dominant emission from bottom quantum wells were found in the V-defect compared to its vicinity. Such enhanced current injection into the bottom part of quantum wells through V-defect results in higher light output power. Reduced external quantum efficiency droops were achieved due to more uniform carrier distribution. The un-encapsulated fabricated chip shows light output power of 172.5 mW and 201.7 mW at 400 mA, and external quantum efficiency drop of 22.3% and 15.4% for the sample without and with large V-defects, respectively. Modified V-defects provide a simple and effective approach to suppress the efficiency droop problem that occurs at high current injection, while improving overall quantum efficiency.

The Uniformity of Surface Passivation After (NH4)2S Treatment Studied by Near-Field Scanning Optical Microscopy

1995 ◽  
Vol 405 ◽  
Author(s):  
Jutong Liu ◽  
T. F. Kuech
Keyword(s):  
Optical Microscopy ◽  
Surface Passivation ◽  
Near Field ◽  
Intensity Variation ◽  
State Density ◽  
Topographic Features ◽  
Spatially Resolved ◽  
Pl Intensity ◽  
Scanning Optical Microscopy ◽  
Near Field Scanning

AbstractWe have achieved spatially resolved room temperature photoluminescence (PL) from MOVPE GaAs (001) surfaces by Near-Field Scanning Optical Microscopy (NSOM). The PL intensity variation was related to the change of surface state density. Using this technique, the uniformity of surface passivation after (NH 4)2S treatment has been studied. We have performed the topography, reflection and PL measurements by NSOM as well as the topography measurements by Atomic Force Microscopy (AFM) on the as grown, etched and sulfur passivated GaAs samples. The uniformity of GaAs with a thin Al0 65Ga0.35As cap layer has also been studied and compared with the (NH 4)2S treatment. We found the sub-micron scale variations in PL intensity which were not correlated to the topographic features. Theoretical modeling has been used to obtain semi-quantitative analysis of the experimental results.

The Uniformity Of Surface Passivation After (NH 4)2S Treatment Studied By Near-Field Scanning Optical Microscopy

1995 ◽  
Vol 406 ◽  
Author(s):  
Jutong Liu ◽  
T. F. Kuech
Keyword(s):  
Optical Microscopy ◽  
Surface Passivation ◽  
Near Field ◽  
Intensity Variation ◽  
State Density ◽  
Topographic Features ◽  
Spatially Resolved ◽  
Pl Intensity ◽  
Scanning Optical Microscopy ◽  
Near Field Scanning

AbstractWe have achieved spatially resolved room temperature photoluminescence (PL) from MOVPE GaAs (001) surfaces by Near-Field Scanning Optical Microscopy (NSOM). The PL intensity variation was related to the change of surface state density. Using this technique, the uniformity of surface passivation after (NH 4)2S treatment has been studied. We have performed the topography, reflection and PL measurements by NSOM as well as the topography measurements by Atomic Force Microscopy (AFM) on the as grown, etched and sulfur passivated GaAs samples. The uniformity of GaAs with a thin Al0.65Ga0.35As cap layer has also been studied and compared with the (NH 4)2S treatment. We found the sub-micron scale variations in PL intensity which were not correlated to the topographic features. Theoretical modeling has been used to obtain semi-quantitative analysis of the experimental results.

Raman imaging with near‐field scanning optical microscopy

1995 ◽  
Vol 67 (17) ◽  
pp. 2483-2485 ◽  
Author(s):  
C. L. Jahncke ◽  
M. A. Paesler ◽  
H. D. Hallen
Keyword(s):  
Optical Microscopy ◽  
Near Field ◽  
Raman Imaging ◽  
Scanning Optical Microscopy ◽  
Near Field Scanning

Investigations of liquid crystals and liquid ambients using near-field scanning optical microscopy

1995 ◽  
Vol 61 (1-4) ◽  
pp. 291-294 ◽  
Author(s):  
Patrick J. Moyer ◽  
Stefan Kämmer ◽  
Karsten Walzer ◽  
Michael Hietschold
Keyword(s):  
Liquid Crystals ◽  
Optical Microscopy ◽  
Near Field ◽  
Scanning Optical Microscopy ◽  
Near Field Scanning
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