Effects of thickneb on optical characteristics and strain distribution of thin-film GaN light-emitting diodes transferred to Si substrates

We investigated the effect of device thickneb on the internal quantum efficiency (IQE) of thin-film GaN light-emitting diodes (LEDs), which were grown on Si substrates and transferred to other Si substrates with reduced film thickneb. It was confirmed by Raman spectroscopy and photoluminescence measurement that the comprebive strain is released and the quantum-confined Stark effect (QCSE) is supprebed after reducing the thickneb. The best IQE of 62.9% was reached with a large supprebion of the band tilting by QCSE, from 7.9meV in the original structure to 2.4meV in the thinnest sample, and this value can compete with that of GaN-based LEDs grown on a sapphire substrate.