Spectroscopy and microscopy of localised and delocalised excitons in InGaN-based light emitting diodes and epilayers

K. P. O'Donnell, R. W. Martin, P. G. Middleton, S. C. Bayliss, I. Fletcher, W. Van Der Stricht, P. Demeester, I. Moerman

Research output: Contribution to journalConference article

10 Citations (Scopus)

Abstract

A comparison of the electroluminescence (EL) spectra and photocurrent (PC) spectra of commercial Nichia 'chip-type' diodes was undertaken in order to clarify the energy relationship between localised and delocalised states. In addition, InGaN epilayers were studied using comparative scanning electron microscopy (SEM), cathodoluminescence (CL) and energy dispersive X-ray (EDX) imaging and optical absorption. The existence of localised states is demonstrated by the so-called 'Stokes' shift' between emission and absorption peaks. After clarifying the definition of this quantity we are able to established that it scales linearly with the emission energy. An explanation of the optical results is found in a detailed picture of the microscopic nature of the InGaN alloys, with regions of relatively high In content found within the matrix, on a size scale much larger than that of a quantum dot.

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Cathodoluminescence
Epilayers
Electroluminescence
Photocurrents
Excitons
Light absorption
Semiconductor quantum dots
Light emitting diodes
Microscopic examination
Diodes
light emitting diodes
excitons
Spectroscopy
microscopy
Imaging techniques
X rays
Scanning electron microscopy
spectroscopy
cathodoluminescence
electroluminescence

Cite this

@article{9ee010944a2f4413a62d42bf6f9ac899,
title = "Spectroscopy and microscopy of localised and delocalised excitons in InGaN-based light emitting diodes and epilayers",
abstract = "A comparison of the electroluminescence (EL) spectra and photocurrent (PC) spectra of commercial Nichia 'chip-type' diodes was undertaken in order to clarify the energy relationship between localised and delocalised states. In addition, InGaN epilayers were studied using comparative scanning electron microscopy (SEM), cathodoluminescence (CL) and energy dispersive X-ray (EDX) imaging and optical absorption. The existence of localised states is demonstrated by the so-called 'Stokes' shift' between emission and absorption peaks. After clarifying the definition of this quantity we are able to established that it scales linearly with the emission energy. An explanation of the optical results is found in a detailed picture of the microscopic nature of the InGaN alloys, with regions of relatively high In content found within the matrix, on a size scale much larger than that of a quantum dot.",
author = "O'Donnell, {K. P.} and Martin, {R. W.} and Middleton, {P. G.} and Bayliss, {S. C.} and I. Fletcher and {Van Der Stricht}, W. and P. Demeester and I. Moerman",
year = "1999",
month = "5",
day = "6",
doi = "10.1016/S0921-5107(98)00343-2",
language = "English",
volume = "59",
pages = "288--291",
journal = "Materials Science and Engineering B",
issn = "0921-5107",
number = "1-3",

}

Spectroscopy and microscopy of localised and delocalised excitons in InGaN-based light emitting diodes and epilayers. / O'Donnell, K. P.; Martin, R. W.; Middleton, P. G.; Bayliss, S. C.; Fletcher, I.; Van Der Stricht, W.; Demeester, P.; Moerman, I.

In: Materials Science and Engineering B: Solid-State Materials for Advanced Technology, Vol. 59, No. 1-3, 06.05.1999, p. 288-291.

Research output: Contribution to journalConference article

TY - JOUR

T1 - Spectroscopy and microscopy of localised and delocalised excitons in InGaN-based light emitting diodes and epilayers

AU - O'Donnell, K. P.

AU - Martin, R. W.

AU - Middleton, P. G.

AU - Bayliss, S. C.

AU - Fletcher, I.

AU - Van Der Stricht, W.

AU - Demeester, P.

AU - Moerman, I.

PY - 1999/5/6

Y1 - 1999/5/6

N2 - A comparison of the electroluminescence (EL) spectra and photocurrent (PC) spectra of commercial Nichia 'chip-type' diodes was undertaken in order to clarify the energy relationship between localised and delocalised states. In addition, InGaN epilayers were studied using comparative scanning electron microscopy (SEM), cathodoluminescence (CL) and energy dispersive X-ray (EDX) imaging and optical absorption. The existence of localised states is demonstrated by the so-called 'Stokes' shift' between emission and absorption peaks. After clarifying the definition of this quantity we are able to established that it scales linearly with the emission energy. An explanation of the optical results is found in a detailed picture of the microscopic nature of the InGaN alloys, with regions of relatively high In content found within the matrix, on a size scale much larger than that of a quantum dot.

AB - A comparison of the electroluminescence (EL) spectra and photocurrent (PC) spectra of commercial Nichia 'chip-type' diodes was undertaken in order to clarify the energy relationship between localised and delocalised states. In addition, InGaN epilayers were studied using comparative scanning electron microscopy (SEM), cathodoluminescence (CL) and energy dispersive X-ray (EDX) imaging and optical absorption. The existence of localised states is demonstrated by the so-called 'Stokes' shift' between emission and absorption peaks. After clarifying the definition of this quantity we are able to established that it scales linearly with the emission energy. An explanation of the optical results is found in a detailed picture of the microscopic nature of the InGaN alloys, with regions of relatively high In content found within the matrix, on a size scale much larger than that of a quantum dot.

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U2 - 10.1016/S0921-5107(98)00343-2

DO - 10.1016/S0921-5107(98)00343-2

M3 - Conference article

VL - 59

SP - 288

EP - 291

JO - Materials Science and Engineering B

T2 - Materials Science and Engineering B

JF - Materials Science and Engineering B

SN - 0921-5107

IS - 1-3

ER -