Luminescence and recombine centre in ZnO/Si films

Abstract

The D⁰h luminescence of ZnO films deposited on p-type Si substrates is produced by metal-organic chemical vapor deposition (MOCVD). After annealing in the air at 700°C for an hour, the photoluminescence (PL) spectra, the I-V characteristics and the deep level transient spectroscopy (DLTS) of the samples are measured. All the samples have a rectification characteristic. DLTS signals show two deep levels of E₁ and E₂. The Gaussian fit curves of the PL spectra at room temperature show three luminescence lines b, c and d, of which b is attributed to the exciton emission. The donor level E₁ measured by DLTS and the location state donor ionization energy E_d of the closely neighboring emission lines c and d are correlated. E₁ is judged as neutral donor bound to hole emission (D⁰h). Moreover, the intensity of the PL spectra decreases while the relative density of E₂ increases, showing that E₂ has the property of a non-radiative center.

Key words： metal-organic chemical vapor deposition (MOCVD); ZnO/p-Si; heterojunction; defect

Acknowledgements

This work was supported by the National Natural Science Foundation of China (Grant Nos. 50472009, 10474091) and the Knowledge Innovation Engineering of the Chinese Academy of Sciences (kjcx2-sw-04-02).

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