Electrical activity of nitrogen acceptors in ZnO films grown by metalorganic vapor phase epitaxy

Abstract

The electrical activity of nitrogen as an acceptor in ZnO has been investigated in two ways. First, nitrogen was introduced by means of diallylamine during metalorganic vapor phase epitaxy (MOVPE) yielding incorporation of nitrogen in the range 1016–1021 cm−3. This led to significant compensation of the natural donors with a minimum electron concentration of 5×1014 cm−3. Second, diffusion of nitrogen was carried out on undoped MOVPE layers under high pressure conditions stemming from the decomposition of NH4NO3. Conversion to p-type conductivity was observed in a systematic way with measured hole concentrations up to 6.5×1017 cm−3.

Chemical Manipulation of High-TCFerromagnetism in ZnO Diluted Magnetic Semiconductors

“…We hypothesize that ligand calcination incorporates Zn 2 -bound nitrogen into the ZnO lattice at crystallite fusion interfaces. The similarity of the nitrogen sources employed in our experiments (R 3 N and R 0 NH 2 ) to those previously used for the preparation of p-type ZnO (e.g., NH 3 , NH 4 NO 3 , N 2 O, NO, and Zn 3 N 2 ) [1,22,23] therefore strongly suggests that the ferromagnetism shown in Fig. 1(a) arises from the introduction of uncompensated p-type defects, tentatively proposed to be N O by analogy to other N-doped ZnO studies [1].…”

“…A related question is whether an analogous post-synthetic p-type perturbation could successfully activate ferromag- netism in epitaxial (low-surface-area) Mn 2 :ZnO. The successful ex situ activation of p-type conductivity in epitaxial ZnO films using NH 4 NO 3 [22] is encouraging in this regard. A third outstanding question pertains to the relationship between T C and defect concentration that would be anticipated from many models [3,6].…”

Manipulating Polar Ferromagnetism in Transition Metal Doped ZnO: Why Manganese Is Different from Cobalt

“…34 As summarized in Fig. 5, aerobic annealing of Mn 2+ : ZnO in the presence of amines increased the 300 K ferromagnetic saturation moments by 300%, but the same experiment decreased the ferromagnetism of Co 2+ : ZnO ͓Figs.…”

High-efficiency micro-energy generation based on free-carrier-modulated ZnO:N piezoelectric thin films

“…Among the group V elements, the ionic size of N is most closely comparable to that of oxygen (O) in terms of radius (r N 3À ¼ 1:68 Å , and r O 2À ¼ 1:38 Å ), and helps to create acceptors (e.g., N substitutes for O sites in the ZnO lattice [N O ]); these acceptors compensated considerably for native donors in ZnO (e.g., Zn i , V O , or H). 8,9,[14][15][16] In this study, we intended to take full advantage of this N-compensatory doping, 26 which is expected to modulate the inherently n-typebiased ZnO conductivity more effectively and make it a more electrically resistive n-type material.…”