Epitaxial N–H-doped Ni1−x O and Ni2O3 with special planar defects by pulsed laser ablation of metallic Ni in aqueous ammonia

N–H-doped nickel oxides with rock salt (R)- and hexagonal (H)-type structures were fabricated by pulsed laser ablation of metallic Ni in aqueous ammonium and characterized by electron microscopy and optical spectroscopy. The R-type Ni1−x O nanoparticles with {100}, {302} and ( $$ \overline{ 2} 33 $$ ) facets showed 1-D 3×(311) commensurate superstructure, whereas the H-type Ni2O3 nanoparticles with (0001), { $$ 10\overline{1} 0 $$ }, { $$ 10\overline{1} 1 $$ } and { $$ 01\overline{1}\,\overline{ 2} $$ } faces showed 1-D 2×{ $$ 01\overline{1}\,\overline{1} $$ } commensurate faulting and ( $$ 1\overline{1} 01 $$ ) twinning. The two phases followed a primary relationship (0001)H//( $$ \overline{1} 1\overline{1} $$ )R; [ $$ 2\overline{1}\,\overline{1} 0 $$ ]H//[011]R and a secondary relationship ( $$ 01\overline{1} 0 $$ )H/( $$ 11\overline{1} $$ )R; [0001]H//[011]R. The overall nanoparticles of N–H-doped nickel oxides have characteristic binding energy and UV absorbance (5.2 eV) for potential optoelectronic and catalytic applications.