3D free carrier localization in light emitting diodes via two-photon optical beam-induced current microscopy

Authors

Godofredo Bautista, Jr. National Institute of Physics, University of the Philippines Diliman
Carlo Blanca National Institute of Physics, University of the Philippines Diliman
Caesar Saloma National Institute of Physics, University of the Philippines Diliman

Abstract

We demonstrate three-dimensional free carrier localization in light emitting diodes (LEDs) using the inherent axial resolution of two-photon optical beaminduced current (2P-OBIC) microscopy. The carrier distribution cannot be mapped out by single photon OBIC (1P-OBIC) in two-dimensions more so in three-dimensions because of the very weak axial discrimination. We utilized a Ti:Sapphire femtosecond laser source operating at 800 nm to derive the 2P-OBIC signal from a 605-nm bandgap LED. The spatial confinement of free carrier generation only at the focus and quadratic dependence of the 2P-OBIC signal with excitation power are the key principles in two-photon excitation. As a consequence, superior image quality evident in the 2P-OBIC images of LEDs are obtained. These features decrease the linear absorption and wide-angle scattering effects plaguing single-photon optical beam-induced current (1P-OBIC) technique thereby increasing the resolution of the imaging system in the axial and lateral directions. Thus, attainment of good axial discrimination in the LED samples is obtained even without a confocal pinhole.

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Issue

2004: Proceedings of the 22nd Samahang Pisika ng Pilipinas Physics Congress

Article ID

SPP-2004-1A-02

Section

Optics and Photonics

Published

2004-10-25

How to Cite

[1]

G Bautista, C Blanca, and C Saloma, 3D free carrier localization in light emitting diodes via two-photon optical beam-induced current microscopy, Proceedings of the Samahang Pisika ng Pilipinas 22, SPP-2004-1A-02 (2004). URL: https://proceedings.spp-online.org/article/view/SPP-2004-1A-02.