P-Type Nitrogen-Doped ZnO Nanoparticles Stable under Ambient Conditions

Abstract

Zinc oxide is considered as a very promising material for optoelectronics. However, to date, the difficulty in producing stable p-type ZnO is a bottleneck, which hinders the advent of ZnO-based devices. In that context, nitrogen-doped zinc oxide receives much attention. However, numerous reviews report the controversial character of p-type conductivity in N-doped ZnO, and recent theoretical contributions explain that N-doping alone cannot lead to p-typeness in Zn-rich ZnO. We report here that the ammonolysis at low temperature of ZnO(2) yields pure wurtzite-type N-doped ZnO nanoparticles with an extraordinarily large amount of Zn vacancies (up to 20%). Electrochemical and transient spectroscopy studies demonstrate that these Zn-poor nanoparticles exhibit a p-type conductivity that is stable over more than 2 years under ambient conditions.

Preparation of nitrogen doped zinc oxide nanoparticles and thin films by colloidal route and low temperature nitridation process

“…After conversion, ZnO 2 nanoparticles present an oxygen content close to the theory (32.8 wt %) and a very low nitrogen content that indicates the good purity of the materials with elimination of the nitrogen containing impurities. At last, the oxygen content measured in ZnO:N sample around 21 wt % suggests the presence of zinc vacancies in the material in good agreement with the DTA/TGA and density analyses as well as with previously reported works [10,18]. The increase of the nitrogen content in ZnO:N sample at 0.5 wt % confirms the effective insertion of nitrogen in the compound along with the slight orange/brown coloration and UV-Vis results [23,24].…”

“…In optoelectronics for instance, the high optical transparency of ZnO thin films coupled with their high electrical conductivity and their strong room temperature luminescence could indeed open up the door to great improvement of technologies such as flat panel displays [7], light emitting diodes [8] or lasers [9]. In a previous study, we have reported the stabilization of p-type nitrogen doped zinc oxide nanoparticles with metal vacancies up to 15-20% (ZnO:N) obtained through the decomposition of zinc peroxide (ZnO 2 ) at low temperature under ammonia flow [10]. Moreover, we have recently demonstrated that the zinc vacancies segregate preferentially at the surface of the ZnO nanoparticles to form a pseudo core-shell structure built upon a stoichiometric zinc oxide core coated with a few angstroms thick Zn-free oxo-hydroxide shell [11].…”

Raman investigation of N‐implanted ZnO: Defects, disorder and recovery

“…Interplay of defects and dopants in semiconductors is very much interesting to explore theoretically as well as for technological purposes . Being a promising optoelectronic material, focused research on ZnO in this direction is going on since the last two decades . Still, the dopant defect combination (in requisite concentration) that can lead to stable p‐type conductivity in ZnO, has not been identified/realized yet.…”

Determining the Nitrogen Content in (Oxy)Nitride Materials

“…This paper reviews some of the techniques to determine the nitrogen content from small (as a dopant in oxides [5,6,7]) to large values (in (oxy)nitrides), as well as oxygen as a co-anion in oxynitride or as an impurity in nitrides. Each method is illustrated with a non-exhaustive list of examples.…”