Single vertical InP nanowire diodes with low ideality factors contacted in-array for high-resolution optoelectronics.

Area of Science:

• Materials Science
• Electrical Engineering
• Optoelectronics

Background:

• Nanowire (NW) devices offer advantages over bulk materials but typically contact entire arrays.
• Ultra-high-resolution displays and photodetectors need individual NW electrical connections.

Purpose of the Study:

• To demonstrate a fabrication scheme for single NW vertical devices within dense NW arrays.
• To compare planarization methods and evaluate transparent top contacts for NW devices.

Main Methods:

• Fabrication of single NW vertical devices by contacting individual NWs in a dense array.
• Comparison of benzocyclobutene and SiO2 planarization techniques.
• Characterization of devices as photodetectors and light-emitting diodes.

Main Results:

• SiO2 planarization significantly improved processing yield and diode quality compared to benzocyclobutene.
• Indium tin oxide top contacts maintained electrical performance, enabling transparency.
• Improved ideality factor from n=14 to n=1.8 (best n=1.5).
• Photodetector detectivities up to 2.45 AW-1 and photocurrent densities up to 185 mAcm-2.
• Devices showed resilience to high current densities (up to 4 × 10^8 mAcm-2).

Conclusions:

• The demonstrated fabrication scheme enables individual NW device fabrication for high-resolution applications.
• SiO2 planarization and transparent top contacts are key for improved device performance and processing.
• These NW devices show significant potential as ultra-high-resolution photodetectors and displays.