scholarly journals Surfactants and digital alloys for strain relief in III-nitride distributed Bragg reflectors and related heterostructures via metal organic vapor phase epitaxy

2011 ◽  
Author(s):  
Lee Ellen Rodak
Keyword(s):  
Vapor Phase ◽  
Vapor Phase Epitaxy ◽  
Bragg Reflectors ◽  
Distributed Bragg Reflectors ◽  
Strain Relief ◽  
Organic Vapor ◽  
Metal Organic ◽  
Digital Alloys

Effect of In as Surfactant on the Growth of AlN/GaN Distributed Bragg Reflectors by Metal Organic Vapor Phase Epitaxy

2008 ◽  
Vol 1108 ◽  
Author(s):  
L E Rodak ◽  
D Korakakis
Keyword(s):  
Refractive Index ◽  
Vapor Phase ◽  
Lattice Mismatch ◽  
Vapor Phase Epitaxy ◽  
Cavity Surface ◽  
Bragg Reflectors ◽  
Distributed Bragg Reflectors ◽  
Organic Vapor ◽  
High Reflectivity ◽  
Metal Organic

AbstractNitride based Distributed Bragg Reflectors (DBRs) have several important applications in current nitride based optoelectronic devices. DBRs can be implemented in resonant cavity light emitting diodes (RCLEDs) to improve light extraction and obtain a more directional emission and in vertical cavity surface emitting lasers (VCSELs) to achieve a lower threshold current. Due the large contrast in refractive index, AlN/GaN DRBs are practical for obtaining high reflectivity and wide bandwidth using relatively few periods. Cracking of the samples is typical for AlN/GaN DRBs due to the tensile strain which results from the 2.4% lattice mismatch and to the difference in thermal expansion coefficients. In addition to cracks, v-shaped defects may also arise in the surface due to surface undulation from stored elastic misfit strain or from threading dislocations that result in scattering and diffraction. Several techniques to reduce the number of cracks and defects have been investigated to obtain smooth surface morphology and high reflectivity, e.g. superlattices to reduce the strain or the growth of AlInGaN/GaN DBRs that offer less lattice mismatch but also lower refractive index contrast. In this work, results of the use of Indium (In) as a surfactant in Metal Organic Vapor Phase Epitaxy (MOVPE) will be discussed. This study addresses AlN/GaN DBR structures designed for peak reflectivity around 465 nm. During the AlN layers’ growth, trimethylindium was introduced to the system and resulted in a reduction of surface cracks. Results of growths at In flow rates are reported and discussed.

Surfactant Effects of Indium on the Growth of AlN/GaN Distributed Bragg Reflectors via Metal Organic Vapor Phase Epitaxy

2009 ◽  
Vol 1195 ◽  
Author(s):  
L E Rodak ◽  
Christopher M Miller ◽  
D Korakakis
Keyword(s):  
Crack Length ◽  
Vapor Phase ◽  
Crack Formation ◽  
Vapor Phase Epitaxy ◽  
Cavity Surface ◽  
Material System ◽  
Bragg Reflectors ◽  
Distributed Bragg Reflectors ◽  
Organic Vapor ◽  
Metal Organic

AbstractDistributed Bragg Reflectors (DBRs) remain critical to the fabrication of various nitride based optoelectronic devices. In particular, DBRs are often employed for cavity formation in Resonant Cavity Light Emitting Diodes (RCLEDs) to enhance and obtain a more directional emission and also in Vertical Cavity Surface Emitting Lasers (VCSELs). As a result, epitaxially grown reflectors are attractive for direct integration in the device, reduced processing requirements, and the formation of narrow cavities. In the III-Nitride material system, Aluminum Nitride (AlN) and Gallium Nitride (GaN) offer a large contrast in refractive index and are therefore well suited for fabricating DBRs with high reflectivity and wide bandwidths using relatively few periods. However, material cracking arising from to the 2.4% lattice mismatch and difference in thermal expansion coefficient decreases reflectivity and is detrimental to the efficiency of subsequent device fabrication. Several techniques, such as superlattice insertion layers or the growth of AlxIn1-xN layers, have been employed to reduce strain and cracking in such structures. In this work, results of the use of indium as a surfactant in the Metal Organic Vapor Phase Epitaxy (MOVPE) of AlN/GaN DBRs will be discussed. Specifically, this study targets AlN/GaN DBRs with peak reflectivity at ranging from 465 nm to 540 nm. Indium has been used as a surfactant during growth by introducing trimethylindium into the system. It has been shown that crack formation is dependent on the flow of the indium precursor despite minimal indium incorporation into the lattice. Image processing techniques were used to quantify the crack length per square millimeter and it was observed that indium has a significant effect on the crack formation and can be used to reduce the total crack length in these structures by a factor of two.

AlN/GaN Distributed Bragg Reflectors Grown via Metal Organic Vapor Phase Epitaxy using GaN Insertion Layers

2012 ◽  
Vol 1396 ◽  
Author(s):  
L. E. Rodak ◽  
J. Peacock ◽  
J. Justice ◽  
D. Korakakis
Keyword(s):  
Refractive Index ◽  
Vapor Phase ◽  
Vapor Phase Epitaxy ◽  
Material System ◽  
Bragg Reflectors ◽  
Distributed Bragg Reflectors ◽  
Organic Vapor ◽  
High Reflectivity ◽  
Short Period ◽  
Metal Organic

ABSTRACTDistributed Bragg Reflectors (DBRs) are an important component of various optoelectronic devices for ultra violet and visible wavelengths. In the III-Nitride material system, Aluminum Nitride (AlN) and Gallium Nitride (GaN) offer a large contrast in refractive index and are therefore well suited for fabricating DBRs with high reflectivity and wide bandwidths using relatively few periods. However, the large lattice and thermal mismatch leads to cracking in these heterostructures. In this work short period superlattice layers have been used to fabricate high reflectivity (> 94%) nitride based DBRs via Metal Organic Vapor Phase Epitaxy. Short period AlN/GaN superlattices containing three to four monolayers of GaN have been employed as the low refractive index layer in DBRs to minimize cracking. Using this technique, crack-free DBRs reflecting from 440-475 nm with up to 25 periods have been fabricated. The technique has been proven to be versatile and resulted in large area yield DBRs grown on a variety of different sapphire substrates.

High-reflective 1.5 μm GaInAsP/InP Bragg reflectors grown by metal organic vapor phase epitaxy

1994 ◽  
Vol 28 (1-3) ◽  
pp. 285-288 ◽  
Author(s):  
K. Streubel ◽  
J. Wallin ◽  
L. Zhu ◽  
G. Landgren ◽  
I. Queisser
Keyword(s):  
Vapor Phase ◽  
Vapor Phase Epitaxy ◽  
Bragg Reflectors ◽  
Organic Vapor ◽  
Metal Organic

Kinetic Analysis of InN Selective Area Metal–Organic Vapor Phase Epitaxy

2008 ◽  
Vol 1 ◽  
pp. 071102 ◽  
Author(s):  
Tomonari Shioda ◽  
Masakazu Sugiyama ◽  
Yukihiro Shimogaki ◽  
Yoshiaki Nakano
Keyword(s):  
Kinetic Analysis ◽  
Vapor Phase ◽  
Vapor Phase Epitaxy ◽  
Organic Vapor ◽  
Selective Area ◽  
Metal Organic
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