Cindy Lee
Pronouns: she/her/hers
Research Mentor(s): Kamruzzaman Khan
Co-Presenter:
Research Mentor School/College/Department: Materials Science and Engineering / Engineering
Presentation Date: April 20
Presentation Type: Poster
Session: Session 1 – 10am – 10:50am
Room: League Ballroom
Authors: Cindy Lee, Kamruzzaman Khan, Elaheh Ahmadi
Presenter: 82
Abstract
Study of Surface Morphology and Optical Properties of InGaN with High In Content on GaN on Sapphire Template The (In,Ga)N material system is attractive for photovoltaic applications, as its optical absorption covers the solar spectrum. Thick indium gallium nitride (InGaN) films (hundreds of nm thick) with an indium nitride (InN) mole fraction larger than 10% are required for these applications. However, the growth of high indium (In)-content InGaN films remains challenging due to 10% lattice mismatch between gallium nitride (GaN) and InN and the large difference between the thermal stabilities of GaN and InN. While the optimum growth temperature of GaN by plasma-assisted molecular beam epitaxy (PAMBE) is around 700 °C-730 °C, the growth temperature of InGaN is typically below 600 °C. Therefore, lower growth temperatures are required to grow InGaN films within the miscibility gap. In this work, we report on the morphology and defects in (In,Ga)N layers with high In content on GaN-on-sapphire template by PAMBE. The surface morphology was studied by atomic force microscopy (AFM) and the defects were characterized by cathodoluminescence (CL). First, we studied the surface morphology of GaN with different growth temperatures. After establishing the optimum growth temperature of the GaN buffer, we investigated the surface morphology of InGaN growth on GaN on sapphire template by changing gallium (Ga) flux and In flux. We studied the defects and optical properties of around 350 nm thick InGaN films by spatially resolved CL measurements. This work provides an overview of high quality growth of thick InGaN films with high In content for a variety of applications, such as solar cells.
Engineering
