Optical observation of donor-bound excitons in hydrogen-implanted ZnO

Abstract

The optical and structural properties of H or He implanted ZnO were investigated using low temperature photoluminescence (PL) and infrared spectroscopy (IR). H implantation is shown to influence the relative luminescence intensities of the donor bound excitons, enhancing the 3.361 eV peak, and changing the overall intensity of the PL spectrum. PL from He implanted ZnO is used to demonstrate that implantation damage is partially responsible for the variations observed in the PL of H implanted ZnO. IR spectra show that the increase in the relative intensity of the 3.361 eV peak coincides with an appearance of the H vibrational mode in the ZnO lattice. Our results indicate that the implanted H forms O–H bonds at Zn vacancies, and that it is these defect complexes which give rise to the shallow donors participating in the observed bound-exciton luminescence at 3.361 eV.

Optical and structural analysis of bulk ZnO samples undoped and rare earth doped by ion implantation

“…We have assumed this donor level as the shallowest H-related donor level is expected to be absent after the annealing procedures in accordance with the authors of Ref. [2].…”

“…More precisely, the near band gap emission is mainly dominated by the recombination of free excitons, shallow donor bound excitons and donor-acceptor pair transitions involving shallow donor levels and deep acceptors [1,2]. Furthermore the presence of broad emission bands in the green spectral region is commonly observed [1,[3][4][5][6][7].…”

Smooth surface, low electron concentration, and high mobility ZnO films on c-plane sapphire

“…6(a) and (b) shows the PL spectra from 13 to 300 K for samples A and C, respectively. Dominant emission peaks at 3.361 eV are evident in both spectra, which are generally attributed to donor bound exciton (D 0 X) in ZnO [25,26]. It is observed that the intensity of D 0 X in sample C is $ 4 times stronger than in sample A while the FWHM of this peak is significantly narrower, which are direct results of improved crystallinity.…”

Defect formation and thermal stability of H in high dose H implanted ZnO

“…More importantly, H implantation in semiconductors has been used to transfer very thin and high quality layers with the SmartCut TM technology. 27 H implanted ZnO has been studied by photoluminescence (PL) spectroscopy, 28,29 Fourier transform infrared spectroscopy, 28,30 Rutherford backscattering spectrometry, 29 secondary ion mass spectrometry (SIMS), 29,31,32 scanning spreading resistance microscopy (SSRM), 31 Hall effect technique, 33 Raman scattering spectroscopy, 34 transmission electron microscopy (TEM), 35 scanning electron microscopy, 35 and positron annihilation spectroscopy (PAS). 36 Monakhov et al 31 have studied the effect of annealing on the electrical properties and H concentration profiles in ZnO implanted with H doses of 5 Â 10 16 and 2 Â 10 17 cm À2 .…”