Active bidirectional electrically-controlled terahertz device based on dimethyl sulfoxide-doped PEDOT:PSS.

Area of Science:

• Terahertz (THz) science and technology
• Organic electronics
• Semiconductor device physics

Background:

• Terahertz (THz) devices are crucial for advanced applications, but achieving high efficiency and broadband modulation remains challenging.
• Organic-inorganic hybrid structures offer tunable properties for optoelectronic devices.
• Electrically controlled modulation in THz devices often requires high power or complex fabrication.

Purpose of the Study:

• To investigate a high-efficiency active bidirectional electrically-controlled terahertz device.
• To explore the use of DMSO-doped PEDOT:PSS and low-power photoexcitation for THz modulation.
• To analyze the device's performance over a broad frequency range and under varying bias conditions.

Main Methods:

• Fabrication of a MEH-PPV/PEDOT:PSS:DMSO/Si/PEDOT:PSS:DMSO hybrid structure.
• Characterization of terahertz (THz) transmission modulation under low-power optical excitation (30 mW) and electrical bias (-0.6 V to 0.5 V).
• Analysis of carrier density characteristics and the role of the p-n junction in modulation.

Main Results:

• Achieved spectrally broadband modulation of THz transmission from -54% to 60% over 0.2–2.6 THz.
• Demonstrated efficient modulation under low-power optical excitation.
• Identified electrically-controlled carrier density in the silicon layer, assisted by the PEDOT:PSS/Si p-n junction, as the mechanism for large amplitude modulation.
• Observed superior performance of bidirectional modulation compared to unidirectional modulation.

Conclusions:

• The developed device exhibits high-efficiency active bidirectional electrically-controlled THz modulation.
• Low-power photoexcitation and the hybrid structure enable broadband THz transmission control.
• The device shows significant potential for advanced terahertz communication systems and active broadband THz devices.