Zinc oxide

Stéphane Jobic (DR), Laurent Cario(DR) (Equipe PMN), Martine Bujoli-Doeuff (MC), Romain Gautier (CR), Camille Latouche (MC), Philippe Deniard (DR), Eric Faulques (DR), Congcong Shang (Postdoctorant, 2014-2017).

Undoped or unintentionally doped zinc oxide is naturally a n-type semiconductor that is widely used in the industry for its pigmental, photocatalytic, piezoelectric, antibacterial and varistor properties. Moreover ZnO exhibits a strong emission in the near ultraviolet (UV) at room temperature. This material therefore has a real interest for devices such as light-emitting diodes and laser diodes emitting in the UV region. Unfortunately, this very promising luminescence is not exploited so far due to the lack of p-type zinc oxide (p-ZnO) necessary for the setting-up of transparent p-n homojunctions.

In that context, we have embarked on the synthesis of p-ZnO by thermal decomposition under ammonia flux of zinc peroxide, ZnO₂. The p-type conductivity of the prepared nanoparticles was first evidenced by photo-electrochemistry and then confirmed both by electrochemical impedance spectroscopy and ultrafast transient absorption measurements. Exceptionally, p-type carriers are stable over periods longer than 2 years and half when stored in ambient conditions. To date, the stabilization of p-type carriers is assigned to the insertion of nitrogen and a strong zinc off-stoichiometry. This Zn deficiency originates from the particle size. Indeed, the smaller the particle, the greater the deviation from the 1:1 stoichiometry, what favors the emergence of acceptor levels. Indeed, oxygen-terminated surfaces are privileged over zinc-terminated surfaces for passivation reasons. This led us to consider these nanoparticles as pseudo-core-shell entities, with a ZnO core and an oxygen rich shell.

Since a significant surface to volume ratio appears to be a key factor in the stabilization of holes in ZnO, the synthesis of zinc-based porous solids has been initiated. This conducts us to the synthesis of ZnC₂O₃H₂, a p-type semiconductor with a white luminesce when zinc nitrate is used as a precursor.

Electrochemical and photoelectrochemical characterization of zinc oxides prepared at 250 ° C., 500 ° C. and 900 ° C. with ZnO₂ for precursor. Only the first one is of the p type and this over periods greater than 2 ½ years.

Heat-shell model applied to ZnO nanoparticles prepared by thermal decomposition of ZnO₂. Let us note the linear evolution of the measured density of the material as a function of the ratio surface / volume.

Zinc-based hybrid compound with p-type conductivity

Involved people

Current: Stéphane Jobic (DR), Laurent Cario(DR) (Equipe PMN), M. Bujoli-Doeuff (MC), Romain Gautier (CR), Camille Latouche (MC), Philippe Deniard (DR), Eric Faulques (DR), Congcong Shang (Postdoctorant, 2014-2017)
Past: Benoît Chavillon (thèse 2011), Adèle Renaud (thèse, 2013), Tengfei Jiang (Postdoctorant, 2014-2016),

Quelques publications

p-type nitrogen doped ZnO nanoparticles stable over two years in ambient conditions
B. Chavillon, L. Cario, A. Renaud, F. Tessier, F. Cheviré, M. Boujtita, Y. Pellegrin, E. Blart, A. Smeigh, L. Hammarström, F. Odobel, S. Jobic
J. Am. Chem. Soc., 134, 464-470, 2012

Unravelling the origin of the giant Zn deficiency in wurtzite type ZnO nanoparticles
A. Renaud, L. Cario, X. Rocquelfelte, P. Deniard, E. Gautron, E. Faulques, T. Das, F. Cheviré, F. Tessier, S. Jobic
Sci. Rep., 5, 12914, 2015

Preparation of nitrogen doped zinc oxide nanoparticles and thin films by colloidal route and low temperature nitridation process
A. Valour, F. Cheviré, F. Tessier, F. Grasset, B. Dierre, T. Jiang, E. Faulques, L. Cario, S. Jobic
Solid State Sci., 54, 30-36, 2016

Embedded 3D Zn-O network in p-type ZnO-like metal organic framework
C. Shang, R. Gautier, T. Jiang, E. Faulques, C. Latouche, M. Paris, L. Cario, M. Bujoli-Doeuff, S. Jobic
Submitted, 2017

Collaborations

ANR and contracts

Financements régionaux: Perle, Perle2 ANR ZnO-typé-p (2013-2017)