Solution-processable zinc oxide based thin films with different aluminum doping concentrations

• Main Authors: Bui Nguyen Quoc Trinh, Truong Dinh Chien, Nguyen Quang Hoa, Do Hong Minh
• Format: Article
• Language: English
• Published: Elsevier 2020-12-01
• Series: Journal of Science: Advanced Materials and Devices
• Subjects: ZnO; AZO; n-type semiconductor; Solar cell; Solution process
• Online Access: http://www.sciencedirect.com/science/article/pii/S246821792030068X

Al doped zinc oxide (AZO) thin films are attempted to be formed on glass substrates via solution processing with 0, 0.5, 1, 2, 3, and 4 at% Al doping concentrations. Analysis of X-ray diffraction patterns and scanning electron microscopy micrographs indicate that the AZO thin films belong to the wurtzite hexagonal structure with (100), (002), (101), (102), (110), (103), (112) and (201) orientations, and show that the grain size of AZO thin films decreases with higher Al doping concentrations. Optical and electrical properties of the AZO thin films are characterized from using a UV/vis spectrometer and a four-probe measurement system, respectively. The AZO thin films obtained have a minimum sheet resistance of 30.41 Ω/sq for the dopant concentration of 1 at%, and a bandgap energy varying from 3.26 eV to 3.16 eV as the Al doping concentration increases from 0 to 4 at%. The maximum figure of merit value of 7.48 × 10−3 (Ω/sq)−1 corresponds to the deposition of the AZO thin film with 2 at% Al doping.