13

Wide Bandgap Semiconductors

for Bioelectronics

Giovana A. Parolin, Alessandra S. Menandro, Rebeca R. Rodrigues, and Laura O. Péres

Laboratory of Hybrid Materials, Institute of Environmental, Chemical, and Pharmaceutical Sciences,

Federal University of São Paulo, São Paulo, Brazil

CONTENTS

13.1 Introduction......................................................................................................................203

13.2 Classes of Wide Bandgap Semiconductors.................................................................204

13.2.1 II−VI Materials...................................................................................................204

13.2.2 III−Nitride...........................................................................................................206

13.2.3 Silicon Carbide – SiC ........................................................................................206

13.3 Fundamental Concepts and Properties of Wide Bandgap Semiconductors.........208

13.3.1 Piezoelectric Effect, Piezoelectric Polarization, and Piezoresistive

Effect ....................................................................................................................208

13.3.2 Direct Bandgap and High Optical Transmittance.......................................209

13.3.3 High Electron Mobility.....................................................................................210

13.3.4 Biocompatibility and Biodegradability..........................................................210

13.4 Which Techniques Have Been Used to Fabricate These Devices?.........................211

13.4.1 Direct Growth of Nanostructures on Flexible Substrates ..........................211

13.4.2 Fabrication Methods of Nanostructures Followed by Transferring

Processes .............................................................................................................213

13.4.2.1 Bottom-Up Growth...........................................................................213

13.4.2.2 Top-Down Growth...........................................................................214

13.4.2.3 Transferring Processes .....................................................................215

13.5 Applications – Where They Can Be Used in Bioelectronics?..................................215

References ....................................................................................................................................217

13.1 Introduction

Wide bandgap (WBG) semiconductors are defined as materials owing a bandgap sub­

stantially in excess, which is greater than 2.2 eV, emerging as efficient materials for ap­

plications in high-performance optoelectronic and electronic devices. The interest of

researchers in WBG compounds has been growing since the late 1980s, resulting in the

inclusion of materials with hexagonal and orthorhombic structures in the range of

semiconductors. WBG semiconductors could be classified mainly into three families’

compounds, the II−VI materials, III−nitride, and SiC, including all their alloys. Among

DOI: 10.1201/9781003263265-13

203