Fabrication Of P-type ZnMgO And ZnO Thin Films Codoped With Al-N And In-N Via DC Reactive Magnetron Sputtering

Zinc oxide (ZnO) is a novel â…¡-â…¥ compound semiconductor with a wide direct bandgap (3.37eV at room temperature) and a hexagonal wurtzite structure. ZnO is a unique material that exhibits optoelectronic, piezoelectric and ferromagnetic multiple properties. In particular, it is a potential candidate for applications in short-wavelength optoelectronic devices, including light emitting diodes (LEDs) and laser diodes (LDs), due to its direct wide-bandgap and high exciton binding energy (60 meV, cf. 25 meV for GaN), which will favor efficient excitonic emission processes at room temperature. What is more, when Mg is added in ZnO, the band gap energy of ZnMgO ternary alloy can be tuned by varying the Mg composition, , which gives ZnO extended application in ultro-violet region.In this paper, p-type ZnMgO alloy codoped with Al-N and ZnO codoped with In-N were synthesized using DC reactive magnetron sputtering (DCRMS). Our work is as below:1. Zn1-xMgxO thin films with good quality were synthesized by DCRMS. The effect of substrate temperature and the content of Mg on the crystallinity, morphology and band gap were studied, and the optimized conditions were concluded. It was also proved that the content of Mg determines the band gap of the Zn1-xMgxO films.2. Based on the experience of synthesis of Zn1-xMgxO films, we fabricated Al-N codoped p-type Zn0.9Mg0.1O films. The as grown samples are with good crystallinity and morphology. The UV-VIS proved that the band gap of codoped films is as the same as Zno.9Mg0.1O films without doping. The effect of substrate temperature on the electrical properties was also studied. P-type Zn0.9Mg0.10 exists in only a certain temperature region, and the optimized temperature should be around 450 ℃⁵00 ℃, which leads the films with a low resistivity and hole concentration of 26 Ωcm and 3.6×10¹⁸cm-3.3. We also tried to fabricate In-N codoped p-type ZnO films by DCRMS. Theas-grown samples showed good crystallinity. The optimized substrate temperature is around 540 ℃. Films grown at this temperature on the glass substrate showed a resistivity of 23.7 Ωcm and hole concentration of 3.51×10-(17) cm-3. The effect of substrate materials on electrical properties was also studied. The codoped films grown on substrate made by SiO2 showed best electrical properties with a low resistivity of 3.12 Ωcm and .high hole concentration of 2.04×10¹⁸cm-3.