Simultaneous enhancement of carrier mobility and concentration via tailoring of Al-chemical states in Al-ZnO thin films

• Main Authors: Manish Kumar, Long Wen, Bibhuti B. Sahu, Jeon Geon Han
• Format: Journal
• Published: 2018
• Subjects: Agricultural and Biological Sciences
• Online Access: https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84934983761&origin=inward; http://cmuir.cmu.ac.th/jspui/handle/6653943832/44322
• Institution: Chiang Mai University

© 2015 AIP Publishing LLC. Simultaneously achieving higher carriers concentration and mobility is a technical challenge against up-scaling the transparent-conductive performances of transparent-conductive oxides. Utilizing one order higher dense (∼1 × 10 < sup > 11 < /sup > cm < sup > -3 < /sup > ) plasmas (in comparison to the conventional direct current plasmas), highly c-axis oriented Al-doped ZnO films have been prepared with precise control over relative composition and chemical states of constituting elements. Tailoring of intrinsic (O vacancies) and extrinsic (ionic Al and zero-valent Al) dopants provide simultaneous enhancement in mobility and concentration of charge carriers. Room-temperature resistivity as low as 4.89 × 10 < sup > -4 < /sup > Ω cm along the carrier concentration 5.6 × 10 < sup > 20 < /sup > cm < sup > -3 < /sup > is obtained in 200 nm thick transparent films. Here, the control of atomic Al reduces the charge trapping at grain boundaries and subdues the effects of grain boundary scattering. A mechanism based on the correlation between electron-hole interaction and carrier mobility is proposed for degenerately doped wide band-gap semiconductors.