Two-step deposition of Al-doped ZnO on p-GaN to form ohmic contacts

Al-doped ZnO (AZO) thin films were deposited directly on p-GaN substrates by using a two-step deposition consisting of polymer assisted deposition (PAD) and atomic layer deposition (ALD) methods. Ohmic contacts of the AZO on p-GaN have been formed. The lowest sheet resistance of the two-step prepared AZO films reached to 145 Ω/sq, and the specific contact resistance reduced to 1.47 × 10^-2 Ω·cm². Transmittance of the AZO films remained above 80% in the visible region. The combination of PAD and ALD technique can be used to prepare p-type ohmic contacts for optoelectronics.