Two-Photon Optical Beam-Induced Current Microscopy of Light-Emitting Diodes
We demonstrate two-photon optical beam-induced current (2P-OBIC) microscopy of light-emitting diodes (LEDs). We utilized a Ti:Sapphire femtosecond laser source operating at 800 nm to derive the 2P-OBIC signal from a 605 nm band-gap LED. The spatial confinement of free carrier generation only at the...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
University of the Philippines
2004-12-01
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| Series: | Science Diliman |
| Subjects: | |
| Online Access: | http://journals.upd.edu.ph/index.php/sciencediliman/article/view/108 |
| Summary: | We demonstrate two-photon optical beam-induced current (2P-OBIC) microscopy of light-emitting diodes (LEDs). We utilized a Ti:Sapphire femtosecond laser source operating at 800 nm to derive the 2P-OBIC signal from a 605 nm band-gap LED. The spatial confinement of free carrier generation only at the focus and the quadratic dependence of the 2P-OBIC signal on 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, the attainment of good axial discrimination in the LED samples is obtained even without a confocal pinhole. In addition, 2P-OBIC images reveal local variations in free carrier densities which are not evident in the single-photon excitation. |
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| ISSN: | 0115-7809 2012-0818 |