Abundant Acceptor Emission from Nitrogen-Doped ZnO Films Prepared by Atomic Layer Deposition under Oxygen-Rich Conditions

Abstract

Nitrogen-doped and undoped ZnO films were grown by thermal atomic layer deposition (ALD) under oxygen-rich conditions. Low-temperature photoluminescence spectra reveal a dominant donor-related emission at 3.36 eV and characteristic acceptor-related emissions at 3.302 and 3.318 eV. Annealing at 800 °C in oxygen atmosphere leads to conversion of conductivity from n- to p-type, which is reflected in photoluminescence spectra. Annealing does not increase any acceptor-related emission in the undoped sample, while in the ZnO:N it leads to a considerable enhancement of the photoluminescence at 3.302 eV. The high resolution cathodoluminescence cross-section images show different spatial distribution of the donor-related and the acceptor-related emissions, which complementarily contribute to the overall luminescence of the annealed ZnO:N material. Similar area of both emissions indicates that the acceptor luminescence comes neither from the grain boundaries nor from stacking faults. Moreover, in ZnO:N the acceptor-emission regions are located along the columns of growth, which shows a perspective to achieve a ZnO:N material with homogeneous acceptor conductivity at least at the micrometer scale.

Zinc Oxide Grown by Atomic Layer Deposition: From Heavily n‐Type to p‐Type Material

“…Low‐temperature (LT) PL and cathodoluminescence (CL) measurements confirmed activation of the p‐type conductivity after the RTP annealing process . It is also independently seen in LT (10 K) micro‐PL spectra measured from a cross section of the ZnO film (see Figure ), in which a He–Cd laser beam emitting at 325 nm was focused to a spot with a diameter of about 1 μm.…”

“…The spatial‐resolved CL images reveal that acceptor‐ and donor‐related emissions have complicated spatial distribution. In the annealed ZnO:N films that show p‐type conductivity, the acceptor emission dominates and it is gathered along the columns of growth . It is qualitatively a different situation than in epitaxial ZnO:N films grown by MBE, where acceptor‐related CL was observed along stacking faults .…”

“…The highest hole mobility, 17.3 cm 2 (Vs) −1 , was observed when nitrogen concentration was at the level 10 19 cm −3 . The related hole concentration was measured as 4.5 × 10 16 cm −3 …”

Controlled Growth of Supported ZnO Inverted Nanopyramids with Downward Pointing Tips

“…The tailoring of zinc oxide chemical, physical, and functional properties as a function of the size and shape of ZnO building blocks offers a huge possibility for a variety of technological end-uses. ,− The latter encompass, among others, transparent conducting oxides, ,, (photo)­catalysts for various processes, ,,− light emitting diodes , and lasers, , electrodes for dye-sensitized ,,, and photoelectrochemical cells, ,,− nanostructured films with antifogging and self-cleaning applications, ,,, as well as nanoscale transducers, field emitters, resonators, ,,, and solid-state gas sensors. ,, Therefore, various preparation routes ,,,, (from wet chemical approaches, ,,,, to hydrothermal/solvothermal processes, ,,,, electrodeposition, ,, atomic layer deposition, , chemical vapor deposition (CVD), ,,,, and evaporation ,,, ) have been proposed to fabricate ZnO-based systems with tailored morphologies and dimensional scales from micro- to nanolevel, with the aim of increasing their performances. , In this regard, beside morphology, the defect content and active area significantly affect the p...…”

Current Transport Mechanisms in Zinc Oxide/Silicon Carbide Heterojunction Light‐Emitting Diodes

“…Nitrogen (N), arsenic (As), phosphorus (P), and antimony (Sb) are promising anionic dopants [11,12] for obtaining the p-type conductivity in ZnO, and there are many reports on successful p-type doping of ZnO. [3,[12][13][14][15][16][17] Rapid thermal annealing (RTA) was usually applied after growth to activate the p-type conductivity; [18] however, diffusion of dopants through p-ZnO/ n-ZnO interface in homojunction structures would be detrimental to the p-n junction, but in the case of heterojunctions (HJs), this problem may be less important.…”