Epitaxial thin film transfer for flexible devices from reusable substrates

Abstract

A new epitaxial thin film transfer method is introduced which utilizes film/substrate systems with sufficiently strong interaction for heteroepitaxial alignment, but with weak adhesion interaction such that inherent stress caused by heteroepitaxy combined with thermomechanical stress causes the deposited structures to separate at the interface. The thin films retain their optical and structural properties following the transfer process to a secondary carrier, leaving the growth substrate for further reuse. We demonstrate the application of this technique by synthesizing a simple crystalline II–VI heterostructure device on sapphire and transferring it to a polysulfone flexible carrier. Devices produced by this method eliminate the need for selective chemical etch layers, ion-implantation or complex post-processing of the growth substrate, reducing processing steps and cost as well as providing the advantage of substrate flexibility compared to what is possible by conventional fabrication techniques.