title: Comparison of Strain in GaN-Based Blue Light-Emitting Diode Grown on Silicon(111) and Sapphire Substrates.
abstract: We compare the strain states and device performances of GaN-based blue light-emitting diodes (LEDs) grown on Si(111) and sapphire substrates. The strain characteristics are investigated using micro-Raman spectroscopy and high-resolution transmission electron microscopy. These analyses reveal that GaN layer grown on Si has a residual tensile strain in contrast to a compressive strain for GaN on sapphire, and quantum wells (QWs) on GaN/Si experience reduced lattice mismatch than those of GaN/sapphire. When external quantum efficiencies of LED on sapphire and Si substrates are compared, the LED on Si shows better efficiency droop characteristics and this is attributed to a decrease in piezo-electric field strength in InGaN/GaN layers owing to reduced lattice mismatch.
authors.forename: K S
authors.initials: KS
authors.lastname: Jeon
authors.forename: J H
authors.initials: JH
authors.lastname: Sung
authors.forename: M W
authors.initials: MW
authors.lastname: Lee
authors.forename: H Y
authors.initials: HY
authors.lastname: Song
authors.forename: E A
authors.initials: EA
authors.lastname: Lee
authors.forename: S O
authors.initials: SO
authors.lastname: Kim
authors.forename: H J
authors.initials: HJ
authors.lastname: Choi
authors.forename: H Y
authors.initials: HY
authors.lastname: Shin
authors.forename: W H
authors.initials: WH
authors.lastname: Park
authors.forename: Y I
authors.initials: YI
authors.lastname: Jang
authors.forename: M G
authors.initials: MG
authors.lastname: Kang
authors.forename: Y H
authors.initials: YH
authors.lastname: Choi
authors.forename: J S
authors.initials: JS
authors.lastname: Lee
authors.forename: D H
authors.initials: DH
authors.lastname: Ko
authors.forename: H Y
authors.initials: HY
authors.lastname: Ryu