Bias-stress effect in 1,2-ethanedithiol-treated PbS quantum dot field-effect transistors

Area of Science:

• Materials Science
• Nanotechnology
• Solid State Physics

Background:

• Field-effect transistors (FETs) are crucial electronic components.
• Lead sulfide (PbS) quantum dots (QDs) offer tunable electronic properties for advanced applications.
• Understanding charge transport and stability in QD films is essential for device performance.

Purpose of the Study:

• To investigate the bias-stress effect in 1,2-ethanedithiol-treated PbS QD-based FETs.
• To elucidate the origin and characteristics of charge trapping within the QD film.
• To explore the influence of QD size and dielectric on the bias-stress phenomenon.

Main Methods:

• Fabrication of top-gated FETs using PbS QD films.
• Electrical characterization including mobility measurements (n-channel and p-channel).
• Analysis of drain-source current decay under bias stress using stretched exponential functions and Arrhenius behavior.

Main Results:

• Ambipolar operation observed with mobilities μ(e) = 8 × 10(-3) cm(2) V(-1) s(-1) and μ(h) = 1 × 10(-3) cm(2) V(-1) s(-1).
• Bias-stress effect observed as a rapid, stretched exponential decay in drain-source current, originating from the QD film.
• Stress in n-channel operation is faster for smaller QDs; p-channel stress is size-invariant. Phenomenon is recoverable.

Conclusions:

• Charge trapping and bias-stress effects in PbS QD FETs are intrinsic to the QD film.
• Field-induced morphological changes likely cause gate field screening.
• Recoverable bias-stress characteristics are promising for optoelectronic device applications.