Fabrication of p-ZnO:Na/n-ZnO:Na homojunction by surface pulsed laser irradiation

Abstract

An ingenious method of preparation of ZnO homojunctions for on-chip integration purposes is proposed, by local multiple pulse laser irradiating (MPLI) ZnO:Na film (NZO). The importance of this method lies in realization of p- and n-ZnO using only one kind of dopant (Na element) with a single layer of NZO film. The p-NZO as prepared by pulsed laser deposition (PLD) easily changes to n type after a couple of hours. However, more than ∼150 times MPLI with laser fluence of 60 mJ cm⁻² can be used to efficiently control the Na dopants to occupy the substitutional (NaZn) sites to realize a more stable p-NZO. The low temperature (6 K) PL spectra of the p-NZO at excitation power of 6 mW and the first principle calculation show that the acceptor energy level is ∼161 meV. The current–voltage (I–V) curve of the p–n NZO homojunction fabricated by local MPLI shows good rectifying behavior, with turn on voltage at ∼2.47 V under forward bias voltage and reverse breakdown voltage bias ∼11.22 V. This convenient p–n junction technique could be used to simplify and improve controllability and accuracy of fabrication of microchip electronic devices.