title: A hybrid fiber-optic photoluminescence measurement system and its application in InGaN/GaN light emitting diode epi-wafer morphology studies.
abstract: We report a fiber optic photoluminescence (PL) measurement system using a novel hybrid probe composed of a series of single mode fiber (SMF) and double-clad fiber (DCF) terminated with a coreless silica fiber (CSF) segment and glass micro-lens formed on its cleaved-facet. The fiber probe provided a good guidance and focusing capability for the excitation photon with a focal length of 125 μm and a beam diameter of 13.6 μm. Utilizing a special DCF-to-DCF coupling scheme, the photoluminescence signals were efficiently collected and delivered to a photodetector with a low loss. Utilizing the proposed system, PL morphology was investigated over a 200 × 200 μm(2) area for two types of InGaN/GaN blue light emitting diode (LED) epi-wafers grown on 1) an un-patterned sapphire substrate (UPSS), and 2) a patterned sapphire substrate (PSS). The uniformity in the relative PL intensity and the spectral uniformity in terms of the peak PL wavelength were experimentally compared and analyzed.
authors.affiliation: Institute of Physics and Applied Physics, Yonsei University, Seoul, South Korea.
authors.forename: Sohee
authors.initials: S
authors.lastname: An
authors.forename: Yong Gon
authors.initials: YG
authors.lastname: Seo
authors.forename: Woohyun
authors.initials: W
authors.lastname: Jung
authors.forename: Minkyu
authors.initials: M
authors.lastname: Park
authors.forename: Jiyoung
authors.initials: J
authors.lastname: Park
authors.forename: Jongki
authors.initials: J
authors.lastname: Kim
authors.forename: Yoonseob
authors.initials: Y
authors.lastname: Jeong
authors.forename: Kyunghwan
authors.initials: K
authors.lastname: Oh
mesh_terms: D004867:Equipment Design; D019544:Equipment Failure Analysis / Q000295:instrumentation*; D005336:Fiber Optic Technology / Q000295:instrumentation*; D008029:Lighting / Q000295:instrumentation*; D008163:Luminescent Measurements / Q000295:instrumentation*; D012666:Semiconductors; D018511:Systems Integration