title: A Study of Piezoelectric Field Related Strain Difference in GaN-Based Blue Light-Emitting Diodes Grown on Silicon(111) and Sapphire Substrates.
abstract: We investigate the strain difference in InGaN/GaN multiple quantum wells of blue light-emitting diode (LED) structures grown on silicon(1 11) and c-plane sapphire substrates by comparing the strength of piezo-electric fields in MQWs. The piezo-electric fields for two LED samples grown on silicon and sapphire substrates are measured by using the reverse-bias electro-reflectance (ER) spectroscopy. The flat-band voltage is obtained by measuring the applied reverse bias voltage that induces a phase inversion in the ER spectra, which is used to calculate the strength of piezo-electric fields. The piezo-electric field is determined to be 1.36 MV/cm for the LED on silicon substrate and 1.83 MV/cm for the LED on sapphire substrate. The ER measurement results indicate that the strain-induced piezo-electric field is greatly reduced in the LED grown on silicon substrates consistent with previous strain measurement results by micro-Raman spectroscopy and high-resolution transmission electron microscopy.
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: 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