title: Piezo-generator integrating a vertical array of GaN nanowires.
abstract: We demonstrate the first piezo-generator integrating a vertical array of GaN nanowires (NWs). We perform a systematic multi-scale analysis, going from single wire properties to macroscopic device fabrication and characterization, which allows us to establish for GaN NWs the relationship between the material properties and the piezo-generation, and to propose an efficient piezo-generator design. The piezo-conversion of individual MBE-grown p-doped GaN NWs in a dense array is assessed by atomic force microscopy (AFM) equipped with a Resiscope module yielding an average output voltage of 228 ± 120 mV and a maximum value of 350 mV generated per NW. In the case of p-doped GaN NWs, the piezo-generation is achieved when a positive piezo-potential is created inside the nanostructures, i.e. when the NWs are submitted to compressive deformation. The understanding of the piezo-generation mechanism in our GaN NWs, gained from AFM analyses, is applied to design a piezo-generator operated under compressive strain. The device consists of NW arrays of several square millimeters in size embedded into spin-on glass with a Schottky contact for rectification and collection of piezo-generated carriers. The generator delivers a maximum power density of ∼12.7 mW cm(-3). This value sets the new state of the art for piezo-generators based on GaN NWs and more generally on nitride NWs, and offers promising prospects for the use of GaN NWs as high-efficiency ultra-compact energy harvesters.
authors.affiliation: Laboratoire de Photonique et de Nanostructures, CNRS UPR20, Université Paris-Saclay, Route de Nozay, F-91460 Marcoussis, France.
authors.forename: N
authors.initials: N
authors.lastname: Jamond
authors.forename: P
authors.initials: P
authors.lastname: Chrétien
authors.forename: F
authors.initials: F
authors.lastname: Houzé
authors.forename: L
authors.initials: L
authors.lastname: Lu
authors.forename: L
authors.initials: L
authors.lastname: Largeau
authors.forename: O
authors.initials: O
authors.lastname: Maugain
authors.forename: L
authors.initials: L
authors.lastname: Travers
authors.forename: J C
authors.initials: JC
authors.lastname: Harmand
authors.forename: F
authors.initials: F
authors.lastname: Glas
authors.forename: E
authors.initials: E
authors.lastname: Lefeuvre
authors.forename: M
authors.initials: M
authors.lastname: Tchernycheva
authors.forename: N
authors.initials: N
authors.lastname: Gogneau