Stoichiometric Control of Lead Chalcogenide Nanocrystal Solids to Enhance Their Electronic and Optoelectronic Device Performance
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- 作者：Soong Ju Oh ; Nathaniel E. Berry ; Ji-Hyuk Choi ; E. Ashley Gaulding ; Taejong Paik ; Sung-Hoon Hong ; Christopher B. Murray ; Cherie R. Kagan
- 刊名：ACS Nano
- 出版年：2013
- 出版时间：March 26, 2013
- 年：2013
- 卷：7
- 期：3
- 页码：2413-2421
- 全文大小：489K
- 年卷期：v.7,no.3(March 26, 2013)
- ISSN：1936-086X
文摘
We investigate the effects of stoichiometric imbalance on the electronic properties of lead chalcogenide nanocrystal films by introducing excess lead (Pb) or selenium (Se) through thermal evaporation. Hall-effect and capacitance鈥搗oltage measurements show that the carrier type, concentration, and Fermi level in nanocrystal solids may be precisely controlled through their stoichiometry. By manipulating only the stoichiometry of the nanocrystal solids, we engineer the characteristics of electronic and optoelectronic devices. Lead chalcogenide nanocrystal field-effect transistors (FETs) are fabricated at room temperature to form ambipolar, unipolar n-type, and unipolar p-type semiconducting channels as-prepared and with excess Pb and Se, respectively. Introducing excess Pb forms nanocrystal FETs with electron mobilities of 10 cm2/(V s), which is an order of magnitude higher than previously reported in lead chalcogenide nanocrystal devices. Adding excess Se to semiconductor nanocrystal solids in PbSe Schottky solar cells enhances the power conversion efficiency.