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

Authors

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

Downloads

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.