III-Nitride Nanomembranes for Photonic and Electronic Applications

Abstract: III-nitride nanomembranes (NMs) represent a new embodiment of the nitride compound semiconductors having identical crystalline perfection and optoelectronic efficacy. The III-nitride NMs are naturally compatible with flexible hosts due to the reduced flexural rigidity and can be incorporated into layered stacks with other two-dimensional materials. A major reason to hinder the nitride NM from realizing devices is the ceramic-like chemical inertness of nitride compound semiconductor, making it difficult to etch or to undercut which resulted in the formation of freestanding NM. Based on a recent discovery of conductivity selective electrochemical etching of GaN, we demonstrated large area GaN NMs with a freestanding thickness less than 150 nm produced from state-of-the-art epitaxial structures. Bright blue light emission from NM light emitting diode (LED) validates the concept of NM-based optoelectronics and points to potentials in flexible applications and heterogeneous integration. In addition to the photonic application, enhancement-mode field effect transistors (FETs) have been fabricated on a SiO2/Si wafer, suggesting that GaN NMs can be a new candidate for flexible electronics requiring high power and high-frequency.