Ink-jet printed ZnO nanowire field effect transistors (APL 91, 043109 2007 )

Self-aligned printing of high-performance polymer thin-film

transistors (IEDM 2006)

Yong-Young Noh, Xiaoyang Cheng, and Henning Sirringhaus

Huai-Yuan Michael TsengEE C235

Inorganic semiconductor nanowire field effect transistors (NW-FETs)

Low cost printing process◦ Large area, flexible electronics◦ But required sub-10um resolution◦ Difficult to form ohmic contact when print Si NW

Self-aligned inkjet printing technique Printing of metal oxide NW (ZnO)

Introduction

Self-aligned inkjet printing 1

Self-aligned inkjet printing 2

Self-aligned inkjet printing 3

cyclohexylbenzene(CHB)

Au lift-off SAM treatment on Au Au nanoparticles printed, de-wet ZnO NW

◦ Chemical vapor deposition on a-plane sapphire substrate

◦ dispersed in IPA/ethylene glycol then inkjet printed

Spin-cast PMMA Print PEDOT:PSS

Process

SAM used = 1H, 1H, 2H,2H-perflourodecanethiolPMMA = polymethyl methacrylatePEDOT:PSS = poly3,4-ethylenedioxithiophene

doped with poly-styrene sulfonate

L=500nm

Improved by heating

Without ZnO

With ZnO

Results

All solution process ZnO NW FETs were demonstrated, however

Performance limited by contact resistance as can be proved by a longer channel length device (2um)

Could be improved by using lower work function metal nanoparticle or SAM treatment on Au

Conclusion