Self-powered photodetectors with a position-controlled array based on ZnO nanoclusters

Area of Science:

• Materials Science
• Optoelectronics
• Nanotechnology

Background:

• Traditional photodetectors often require external power sources.
• Improving light trapping and reducing optical loss are key challenges in photodetector design.
• Zinc oxide (ZnO) nanostructures offer promising optoelectronic properties.

Purpose of the Study:

• To develop a self-powered ultraviolet (UV) photodetector (PD) utilizing a position-controlled array of zinc oxide (ZnO) nanoclusters (NCs).
• To investigate the performance of this novel ZnO-based PD structure under UV illumination without external bias.
• To compare the performance of PDs fabricated on silicon (Si) and gallium nitride (GaN) substrates.

Main Methods:

• Fabrication of a position-controlled ZnO nanocluster array on Si and GaN substrates.
• Characterization of the photodetector's performance under UV light (365 nm) at zero bias.
• Measurement of key parameters including responsivity, external quantum efficiency (EQE), photocurrent, and on/off ratio.

Main Results:

• The ZnO NC array PD successfully detected UV light at zero bias, generating its own carriers.
• The Si-based PD achieved a responsivity of 14.1 mA/W and EQE of 4.79%.
• The GaN-based PD demonstrated higher performance with responsivity up to 59.9 mA/W, EQE of 20.04%, photocurrent of 10^-5 A, and an on/off ratio of 174.

Conclusions:

• The proposed self-powered ZnO NC array photodetector exhibits significant potential for UV detection applications.
• The innovative array structure enhances light trapping and reduces loss, enabling efficient zero-bias operation.
• The GaN-based device shows superior performance, highlighting its suitability for demanding optoelectronic applications.