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Published on: August 23, 2012
Solution-based stoichiometric control over charge transport in nanocrystalline CdSe devices
David K Kim1, Aaron T Fafarman, Benjamin T Diroll
1Department of Materials Science and Engineering, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States.
ACS Nano
|September 20, 2013
Summary
Chemically altering the surface of cadmium selenide nanowire field-effect transistors (FETs) impacts carrier transport. Surface stoichiometry critically influences doping efficacy, enabling tunable electronic properties in these semiconductor devices.
Area of Science:
- Materials Science
- Nanotechnology
- Solid State Physics
Background:
- Colloidal semiconductor nanowires (NWs) are promising for electronic devices.
- Surface chemistry significantly influences the electronic properties of nanomaterials.
- Controlling surface stoichiometry is key to tuning device performance.
Purpose of the Study:
- To investigate the effect of surface stoichiometry on carrier transport in cadmium selenide (CdSe) nanowire field-effect transistors (FETs).
- To explore how surface adatoms (cadmium, selenium, sulfur) influence electronic behavior.
- To determine the impact of surface composition on indium doping efficiency.
Main Methods:
- Fabrication of CdSe NW FETs.
- Room-temperature wet-chemical modification of NW surfaces with adatoms.
- Surface composition analysis using energy-dispersive X-ray spectroscopy (EDS) and inductively coupled plasma-atomic emission spectroscopy (ICP-AES).
- Electrical characterization of NW FETs before and after doping.
Main Results:
- Surface cadmium treatment enhanced electron currents, while selenium or sulfur treatments suppressed them.
- Indium doping efficacy was highly dependent on surface composition.
- Selenium-enriched, indium-doped NWs became semimetallic.
- Sulfur-enriched, indium-doped NWs showed significantly enhanced electron currents (ION/IOFF >10^6).
- Low-temperature measurements indicated surface-based indium-chalcogen interactions.
Conclusions:
- Surface stoichiometry critically controls carrier transport and doping in CdSe NW FETs.
- Wet-chemical surface modification offers a route to tune electronic properties.
- Indium doping involves surface interactions with chalcogens, relevant for nanocrystal films.
- Tailoring NW surface composition is essential for advanced nanomaterial-based electronics.
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