III-Nitride LED Structures on Sidewall Grown Semipolar Facets

North Carolina State University, Raleigh NC

Investigators

Abstract

Technical Description: This research project focuses on the development and understanding of a new approach for fabrication of semipolar III-nitride structures for light emitting diode (LED) applications. The method is based on stripe patterning of c-plane GaN templates and deep-groove etching, followed by sidewall re-growth to form semipolar facets on which InGaN/GaN quantum wells are grown. The dominant lateral growth modes are expected to result in a significantly reduced dislocation density. The LEDs based on the semipolar materials should benefit from a reduced polarization-induced field and enhanced indium incorporation, and are regarded as a promising solution of the "green gap" problem in the nitride LED technology. By employing a variety of structural and optical characterization, the research team studies the preferential faceting formation and dislocation reduction for different patterning methods as well as the growth kinetics for different semipolar facets; the indium and doping-element incorporation efficiency in different directions in lateral growth regimes; the strain and internal quantum efficiency in structures with different semipolar alignments. Non-technical Description: The knowledge gained from this research project can be of significant importance for establishing a design of low defect-density, cost-efficient InGaN/GaN quantum-well structures with semipolar alignment, and for guiding technological development of light emitting diodes with improved internal quantum efficiency in blue-green region. The research activities leverage the PIs' previously established national and international collaborations. The project provides training of graduate students by exposing them to comprehensive, application-motivated academic research through curriculum development, guest lectures and seminars. The project intends to involve and support women and underrepresented minorities, as well as high-school students conducting summer science research.