Dresden 2026 – scientific programme
Parts | Days | Selection | Search | Updates | Downloads | Help
HL: Fachverband Halbleiterphysik
HL 37: Nitrides II – Designed properties and LED
HL 37.2: Talk
Thursday, March 12, 2026, 09:45–10:00, POT/0006
Detailed nano-characterization of structural and optical properties of a red-emitting InGaN LED — •N. Dreyer1, F. Bertram1, G. Schmidt1, J. Christen1, Z. Chen2, and X. Wang2 — 1Otto-von-Guericke-University Magdeburg, Germany — 2Peking University, Beijing, China
A fully processed and operating red InGaN LED was grown by MOVPE on a GaN/sapphire template. The active region, which consists of three identical stacks, is surrounded by n- and p-GaN with an EBL. Each stack contains three quantum wells with different indium concentrations: two with a low indium concentration for strain relaxation, and one subsequently grown red-emitting quantum well (RQW). The structure was characterized using scanning transmission electron microscopy (STEM) and the orientation of the Burgers vector (edge- or screw type dislocation) was determined. Cross-sectional cathodoluminescence performed directly in STEM shows broad band-to-band recombination in the n-GaN at T = 17 K which is caused by band gap renormalization and conduction band filling. Line shape analysis of this emission band yields a charge carrier density of 6 × 1018 cm−3. The vertical evolution of the RQW emission exhibits a shift of 123 meV within the active region. Furthermore, the lateral homogeneity of the RQW emission will be examined. A blue-shift of the RQW emission of up to 365 meV was found around defects. The vertical and lateral trapping processes of excess carriers will be discussed in detail. The capture length of the bottom RQW was found to be 78 nm using highly spatially resolved vertical linescans across the active region.
Keywords: Cathodoluminescence; Red LED; Scanning transmission electron microscopy; InGaN MQW