We control the stoichiometry of nanocrystal thin films and therefor the carrier statistics and polarity of charge transport in nanocrystal thin film solids. For example, in lead chalcogenide nanocrystal thin films introduction of excess lead, a low lying donor in the lead chalcogenides, n-dopes the thin films. In complement, the addition of excess chalcogen, an acceptor in the lead chalcogenides, p-dopes the thin films. We use stoichiometric imbalance to control the carrier type, concentration and mobility of carriers in nanocrystal thin films and demonstrate electron mobilities of 10 cm2/Vs in lead chalcogenide nanocrystal thin films.
Schematic and (inset) scanning electron micrograph of a PbSe nanocrystal thin film exchanged at room temperature with thiocyanate and integrated as the channel in field-effect transistors. Transfer characteristics of PbSe nanocrystal thin film transistors as a function of increased amount of evaporated lead and of evaporated selenium.
Stoichiometric Control of Lead Chalcogenide Nanocrystal Solids to Enhance Their Electronic and Optoelectronic Device Performance
Soong Ju Oh, Nathaniel E. Berry, Ji-Hyuk Choi, E. Ashley Gaulding, Taejong Paik, Sung-Hoon Hong, Christopher B. Murray, and Cherie R. Kagan ACS Nano
, 7 (3)
Designing High-Performance PbS and PbSe Nanocrystal Electronic Devices through Stepwise, Post-Synthesis, Colloidal Atomic Layer Deposition
Soong Ju Oh, Nathaniel E. Berry, Ji-Hyuk Choi, E. Ashley Gaulding, Hangfei Lin, Taejong Paik, Benjamin. T. Diroll, Shin Muramoto, Christopher B. Murray, and Cherie R. Kagan NANO Letters
, 14 (3)
Engineering Charge Injection and Charge Transport for High Performance PbSe Nanocrystal Thin Film Devices and Circuits
Soong Ju Oh, Zhuqing Wang, Nathaniel E. Berry, Ji-Hyuk Choi, Tianshuo Zhao, E. Ashley Gaulding, Taejong Paik, Yuming Lai, Christopher B. Murray, and Cherie R. Kagan Nano Letters
, 14 (11)