Photoluminescence (PL) technique has demonstrated the powerful capability for practical application to wafer inspections in III-V compound semiconductor production. This paper describes the principle and the physics behind the variation of PL wavelength with laser excitation power density. We discuss the effect of GaN cap thickness on the PL measurements. This is especially relevant to LED manufacturers where thick GaN caps are commonly used and to PL metrology of InGaN MQW laser structures. A methodology was proposed to select the most appropriate laser and set of excitation conditions to achieve matching between PL and electroluminescence (EL) wavelengths for common Blue and Green LED structures.

Date Published: 3 February 2009
PDF: 9 pages
Proc. SPIE 7231, Light-Emitting Diodes: Materials, Devices, and Applications for Solid State Lighting XIII, 72310P (3 February 2009); doi: 10.1117/12.814665

Published in SPIE Proceedings Vol. 7231:
Light-Emitting Diodes: Materials, Devices, and Applications for Solid State Lighting XIII
Klaus P. Streubel; Heonsu Jeon; Li-Wei Tu, Editor(s)