Correlation of Composition, Microstructure, and Strain at InGaN/GaN Interfaces with Optoelectronic Properties of III-Nitride-Based Light-Emitting Diodes
EMSL Project ID
40066
Abstract
In the proposed research we seek to address critical materials issues in GaN-based light emitting diodes (LEDs) for future solid-state lighting applications. Solid-state lighting has enormous potential to improve energy efficiency relative to current lighting technologies. However, materials-related issues associated with efficiency drop in LEDs and shifts in wavelength must be solved for cost-effective solid-state lighting to be realized. The objectives of this proposal are to investigate a likely cause of efficiency drop, namely, variations in composition within the active layers and interfacial roughness within the multi-quantum well (MQW). The atomic 'roughness' will be produced and controlled by varying the amount of strain introduced into the MQW from a compositionally graded layer underlying the former. Another unique component of this study will be the growth of the graded layer and the MQWs on GaN(0001) substrates. We propose to use atom probe tomography at EMSL to investigate the chemical composition of green-emitting In0.25Ga0.75N MQW structures grown on GaN substrates at subnanometer resolution. We further propose to employ convergent beam electron diffraction within the ultra-high resolution FEI Titan transmission electron microscope to determine the strain within each quantum well and to correlate this strain with the degree of chemical roughness determined via the atom probe tomography studies. The composition, roughness and microstructure analyses using the atom probe and microscopy techniques at EMSL will be used in combination with techniques (e.g., AFM, XRD, fluorescence microscopy, and electroluminescence) at Carnegie Mellon University to assemble a comprehensive set of data on composition and microstructure in In.26Ga.74N/GaN MQWs as a function of strain at different length scales. The goals of the proposed studies fit within EMSL's 'Science of Interfacial Phenomena' Science Theme.
Project Details
Project type
Large-Scale EMSL Research
Start Date
2010-10-01
End Date
2013-09-30
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members
Related Publications
Liu F, L Huang, RF Davis, LM Porter, DK Schreiber, SVNT Kuchibhatla, V Shutthanandan, S Thevuthasan, E Preble, T Paskova, and KR Evans. 2014. "Composition and Interface Analysis of InGaN/GaN Multiquantum-Wells on GaN Substrates Using Atom Probe Tomography." Journal of Vacuum Science and Technology B--Microelectronics and Nanometer Structures 32(5):Article No. 051209. doi:10.1116/1.4893976
Singh A, T Nelson, J Belot, T Young, NR Dhumal, T Kowalewski, RD McCullough, P Nachimuthu, S Thevuthasan, and LM Porter. 2011. "Effect of Self-Assembled Monolayers on Charge Injection and Transport in Poly(3-hexylthiophene)-Based Field-Effect Transistors at Different Channel Length Scales." ACS Applied Materials & Interfaces 3(8):2973-2978. doi:10.1021/am200449x