title: Nonradiative energy transfer between colloidal quantum dot-phosphors and nanopillar nitride LEDs.
abstract: We present in this communication our study of the nonradiative energy transfer between colloidal quantum dot (QD) phosphors and nitride nanopillar light emitting diodes (LEDs). An epitaxial p-i-n InGaN/GaN multiple quantum-well (QW) heterostructure was patterned and dry-etched to form dense arrays of nanopillars using a novel etch mask consisting of self-assembled In3Sn clusters. Colloidal QD phosphors have been deposited into the gaps between the nanopillars, leading to sidewall coupling between the QDs and InGaN QW emitters. In this approach, close QW-QD contact and a low-resistance design of the LED contact layer were achieved simultaneously. Strong non-radiative energy transfer was observed from the InGaN QW to the colloidal QD phosphors, which led to a 263% enhancement in effective internal quantum efficiency for the QDs incorporated in the nanopillar LEDs, as compared to those deposited over planar LED structures. Time-resolved photoluminescence was used to characterize the energy transfer process between the QW and QDs. The measured rate of non-radiative QD-QW energy-transfer agrees well with the value calculated from the quantum efficiency data for the QDs in the nanopillar LED.
authors.affiliation: Department of Engineering Science and Mechanics, Penn State University, University Park, PA 16802, USA.
authors.forename: Fan
authors.initials: F
authors.lastname: Zhang
authors.forename: Jie
authors.initials: J
authors.lastname: Liu
authors.forename: Guanjun
authors.initials: G
authors.lastname: You
authors.forename: Chunfeng
authors.initials: C
authors.lastname: Zhang
authors.forename: Suzanne E
authors.initials: SE
authors.lastname: Mohney
authors.forename: Min Joo
authors.initials: MJ
authors.lastname: Park
authors.forename: Joon Seop
authors.initials: JS
authors.lastname: Kwak
authors.forename: Yongqiang
authors.initials: Y
authors.lastname: Wang
authors.forename: Daniel D
authors.initials: DD
authors.lastname: Koleske
authors.forename: Jian
authors.initials: J
authors.lastname: Xu