Low Temperature Aqueous Solution Route to Reliable p-Type Doping in ZnO with K: Growth Chemistry, Doping Mechanism, and Thermal Stability

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• 作者：Chuan Beng Tay ; Jie Tang ; Xuan Sang Nguyen ; Xiao Hu Huang ; Jian Wei Chai ; Venky T. Venkatesan ; Soo Jin Chua
• 刊名：The Journal of Physical Chemistry C
• 出版年：2012
• 出版时间：November 15, 2012
• 年：2012
• 卷：116
• 期：45
• 页码：24239-24247
• 全文大小：590K
• 年卷期：v.116,no.45(November 15, 2012)
• ISSN：1932-7455

文摘

In this paper, we identified how the growth environment chemistry can critically influence the type and nature of the incorporated K defect in ZnO films grown using the aqueous solution route, which explains the switching between p- and n-type conductivities under different doping or thermal annealing conditions. This was achieved by relating the growth environment to the structural, optical, and electrical characteristics of the films. The thermal behavior of these defects up to 700 掳C confirms the proposed doping mechanism. It is found that the best route to realizing p-type conductivity is through minimizing the amount of K_i and K_Zn鈥揔_i complexes because films with high concentrations of K_i have a slow p-type recovery caused by the slow out-diffusion of K_i. The highest hole concentrations for as-grown films and those that were annealed at 700 掳C for 30 min were 2.6 脳 10¹⁶ and 3.2 脳 10¹⁷ cm^鈥?, respectively. The upper limit for p-type doping using this route appears to be about mid-10¹⁷ cm^鈥?. Our results show that the low temperature aqueous solution synthesis route of ZnO:K is a promising solution toward reliable p-type conductivity for future device applications.