Electrical and Computer Engineering ETDs

Publication Date

Spring 4-15-2019


In order to tackle vertical transport, lateral transport must be better understood. There are added challenges to determining the lateral bulk carrier concentration in narrow bandgap materials due to the potential for electron accumulation at the surface of the material and at its interface with the layer grown directly below it. Electron accumulation layers form high conductance electron channels that can dominate both resistivity and Hall-Effect transport measurements. Therefore, to correctly determine the lateral bulk concentration and mobility, temperature- and magnetic-field-dependent transport measurements in conjunction with Multi-Carrier Fit (MCF) analysis were utilized on a series of p-doped InAs0.91Sb0.09 samples on GaSb substrates. The samples are etched to different thicknesses, and variable-field measurements are utilized to assist in confirming whether a carrier species represents bulk, interface or surface conduction.

Secondly, n-type temperature- and magnetic-field dependent measurements on InAsSb and InAs/InAsSb T2SLs materials were performed to extract the lateral transport properties for all the carriers present in each sample under two different doping concentrations (Non-Intentionally Doped or NID and Silicon-doped). For lateral transport measurements, NRL MULTIBANDS® simulations were utilized to extract and compare the interface carriers for each sample. Lastly, substrate-removed, Metal-Semiconductor-Metal (MSM) devices were fabricated to extract vertical transport mobilities, while conventional Van der Pauw structures were used for lateral measurements. To accurately determine the lateral and vertical transport properties in the presence of multiple carrier species, Multi-Carrier Fit (MCF) and High-Resolution Mobility Spectrum Analysis (HR-MSA) were employed.


Magneto-Resistance, Multi-Carrier Analysis, Substrate Removal, Vertical transport, Lateral Transport, Infrared Detectors


Army Research Office, Air Force Research Laboratory,

Document Type




Degree Name

Electrical Engineering

Level of Degree


Department Name

Electrical and Computer Engineering

First Committee Member (Chair)

Dr. Ganesh Balakrishnan

Second Committee Member

Dr. Francesca Cavallo

Third Committee Member

Dr. Sanjay Krishna

Fourth Committee Member

Dr. Christian Morath

Fifth Committee Member

Dr. Elizabeth Steenbergen