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HL: Fachverband Halbleiterphysik

HL 72: Nitrides: Devices

HL 72.7: Vortrag

Donnerstag, 23. März 2017, 11:30–11:45, POT 06

Molecular control over Ni/GaN Schottky barrier diode using Thiol Porphyrin — •Manjari Garg¹, Tejas R. Naik², Subramaniyam Nagarajan³, V. Ramgopal Rao¹, and Rajendra Singh¹ — ¹Wide Bandgap Semiconductor Lab, Department of Physics, Indian Institute of Technology Delhi, Hauz Khas, New Delhi-110016 — ²Indian Institute of Technology Bombay — ³Aalto University Finland

The present work aims to investigate the control of self-assembled monolayers SAM of Thiol- Porphyrin on the electrical characteristics of GaN based Schottky barrier diode. In this work, SAM of Thiol-Porphyrin TTPSH organic molecules were sandwiched between Nickel metal and GaN semiconductor to tune the work function. The chemisorption of TTPSH SAM on GaN surface was confirmed by using Water contact angle measurements, XPS and AFM. KPFM revealed that the GaN surface potential was reduced from 950 mV to 750 mV after the adsorption of SAM on GaN. A decrease in the surface potential of semiconductor side of the metal-semiconductor interface implies decrease in workfunction of semiconductor which may lead to an increase in Schottky barrier height. Ni metal was deposited on the molecularly modified GaN surface and was electrically characterized by current-voltage measurements. A significant increase in Schottky barrier height and a decrease in reverse bias leakage current by four orders of magnitude was obtained. An increase in the photoluminescence intensity of GaN at 365 nm wavelength shows that surface passivation of GaN is occurring, which leads to the improvement of electrical characteristics of the diodes.