PhD Defense: Design of Indium Arsenide nanowire sensors for pH and biological sensing and low temperature transport through p-doped Indium Arsenide nanowires

PhD defense by Shivendra Upadhyay

Time: 29 November 2013, 13:15

Place: HCØ building, Auditorium 8

Supervisor
Professor Jesper Nygård, Niels Bohr Institute, Faculty of Science,
University of Copenhagen, Denmark

Assessment committee
Professor Charles Marcus (chair), Center for Quantum Devices, Niels Bohr
Institute, Faculty of Science, University of Copenhagen, Denmark

Lecturer (privatdozent) Michel Calame, Department of Physics, University
of Basel, Switzerland

Associate Professor Winnie Edith Svendsen, Department of Micro- and
Nanotechnology, Technical University of Denmark

Abstract:

Design of Indium Arsenide nanowire sensors for pH and biological sensing
and low temperature transport through p-doped Indium Arsenide nanowires

With the goal of real time electrical detection of chemical and biological
species, nanowires have shown great promise with high sensitivity due to
their large surface to volume ratio. While the focus of such electrical
detection has shifted to one dimensional semiconductor nanostuctures,
Silicon remains the primary material of choice. This research is about
investigating Indium Arsenide nanowires as alternative platform for
sensing charged species - chemical and biological, in solution.

Starting with nanowires grown via molecular beam epitaxy in an ultra-high
vacuum chamber, we discuss the fabrication of nanowire transistors using
UV and electron beam lithography as well as the steps to encapsulate the
nanowire transistors into a sensor. Several iterations of experiments
demonstrating pH sensitivity of the NW sensor are presented.

Having established and tested a stable sensing platform via pH sensing, we
apply the same to a more complex system - proteins. The sensing protocol
involves the functionalization of the sensor surface with a receptor
protein followed by the addition of the protein of interest. Sensor
response to oppositely charged proteins is used to confirm the sensitivity
of the sensor to the protein charge.

Read the complete thesis here:
https://qdev.nbi.ku.dk/student_theses/pdf_files/PhDThesis_Upadhyay.pdf/