Wide Bandgap III-Nitride Nanomembranes for Optoelectronic Applications

Abstract

Single crystalline nanomembranes (NMs) represent a new embodiment of semiconductors having a two-dimensional flexural character with comparable crystalline perfection and optoelectronic efficacy. In this Letter, we demonstrate the preparation of GaN NMs with a freestanding thickness between 90 to 300 nm. Large-area (>5 × 5 mm(2)) GaN NMs can be routinely obtained using a procedure of conductivity-selective electrochemical etching. GaN NM is atomically flat and possesses an optical quality similar to that from bulk GaN. A light-emitting optical heterostructure NM consisting of p-GaN/InGaN quantum wells/GaN is prepared by epitaxy, undercutting etching, and layer transfer. Bright blue light emission from this heterostructure validates the concept of NM-based optoelectronics and points to potentials in flexible applications and heterogeneous integration.

One-step fabrication of porous GaN crystal membrane and its application in energy storage

“…With these properties, GaN has potential for a wide range of applications in manufacturing next-generation optoelectronics and high-power and high-frequency devices3. Single crystal GaN membranes have recently attracted much attention because of its unique electronic, optoelectronic, and mechanical properties4567. GaN membrane-based light-emitting diodes4, normally off enhancement-type GaN membrane metal oxide semiconductor transistors5, and GaN membrane-based flexible optoelectronic devices6 have been fabricated.…”

“…Single crystal GaN membranes have recently attracted much attention because of its unique electronic, optoelectronic, and mechanical properties4567. GaN membrane-based light-emitting diodes4, normally off enhancement-type GaN membrane metal oxide semiconductor transistors5, and GaN membrane-based flexible optoelectronic devices6 have been fabricated. These devices exhibit excellent performance, especially in terms of energy storage; n-type single-crystal GaN porous membrane was used as electrode of the supercapacitor, which exhibits excellent cycling lifespan and ultrahigh power density7.…”

“…Significant efforts have been made to prepare GaN membranes, including laser9, chemical10, electrochemical45611, and mechanical liftoff on suitable buffer layers1213. Despite these developments however, established methods contain multiple steps and sometimes require utilization of expensive equipment, which greatly hinder the further development of GaN crystal membranes in practical application.…”

(Invited) Applications of Electrochemistry for Novel Wide Bandgap GaN Devices

“…Depending on the layer conductivity and applied bias, the EC etching may cause no effect, nanoscale porosification, or complete etching of GaN (7). The EC etching has been applied to different areas of GaN material and device technologies, including layer separation, the preparation of flexible GaN membrane devices, and the formation of distributed Bragg reflector (DBR) for photonic applications (8,9,10).…”

Chemical exfoliation and optical characterization of threading-dislocation-free gallium-nitride ultrathin nanomembranes

“…These devices take advantage of the high crystalline quality, and thus high optical efficiencies, of the nanomembranes combined with their two dimensional low flexural rigidity. For example, nanomembrane field effect transistors (FETs) 4 and light emitting diodes (LEDs) 5 have been successfully demonstrated having electrical and optical properties similar to their bulk counterparts but operating on flexible substrates. There are currently several demonstrated techniques for the exfoliation of GaN nanomembranes, each tacking advantage of a different GaN property.…”