title: Three dimensional characterization of GaN-based light emitting diode grown on patterned sapphire substrate by confocal Raman and photoluminescence spectromicroscopy.
abstract: We performed depth-resolved PL and Raman spectral mappings of a GaN-based LED structure grown on a patterned sapphire substrate (PSS). Our results showed that the Raman mapping in the PSS-GaN heterointerface and the PL mapping in the InxGa1-xN/GaN MQWs active layer are spatially correlated. Based on the 3D construction of E2(high) Raman peak intensity and frequency shift, V-shaped pits in the MQWs can be traced down to the dislocations originated in the cone tip area of PSS. Detail analysis of the PL peak distribution further revealed that the indium composition in the MQWs is related to the residual strain propagating from the PSS-GaN heterointerface toward the LED surface. Numerical simulation based on the indium composition distribution also led to a radiative recombination rate distribution that shows agreement with the experimental PL intensity distribution in the InxGa1-xN/GaN MQWs active layer.
authors.affiliation: Dept. of Photonics &Institute of Electro-Optical Engineering, National Chiao Tung University, Hsinchu 30050, Taiwan.
authors.forename: Heng
authors.initials: H
authors.lastname: Li
authors.affiliation: Center for Condensed Matter Sciences, National Taiwan University, 10617, Taipei, Taiwan.
authors.forename: Hui-Yu
authors.initials: HY
authors.lastname: Cheng
authors.affiliation: Center for Condensed Matter Sciences, National Taiwan University, 10617, Taipei, Taiwan.
authors.forename: Wei-Liang
authors.initials: WL
authors.lastname: Chen
authors.affiliation: Center for Condensed Matter Sciences, National Taiwan University, 10617, Taipei, Taiwan.
authors.forename: Yi-Hsin
authors.initials: YH
authors.lastname: Huang
authors.affiliation: Graduate Institute of Photonics and Optoelectronics and Department of Electrical Engineering, National Taiwan University, Taipei, 10617, Taiwan.
authors.forename: Chi-Kang
authors.initials: CK
authors.lastname: Li
authors.affiliation: Dept. of Photonics &Institute of Electro-Optical Engineering, National Chiao Tung University, Hsinchu 30050, Taiwan.
authors.forename: Chiao-Yun
authors.initials: CY
authors.lastname: Chang
authors.affiliation: Graduate Institute of Photonics and Optoelectronics and Department of Electrical Engineering, National Taiwan University, Taipei, 10617, Taiwan.
authors.forename: Yuh-Renn
authors.initials: YR
authors.lastname: Wu
authors.affiliation: Dept. of Photonics &Institute of Electro-Optical Engineering, National Chiao Tung University, Hsinchu 30050, Taiwan.
authors.forename: Tien-Chang
authors.initials: TC
authors.lastname: Lu
authors.affiliation: Center for Condensed Matter Sciences, National Taiwan University, 10617, Taipei, Taiwan.
authors.forename: Yu-Ming
authors.initials: YM
authors.lastname: Chang