Novel approaches to the fabrication of nanoscale devices

Balakrishnan, Nilanthy (2015) Novel approaches to the fabrication of nanoscale devices. PhD thesis, The University of Nottingham.

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This thesis describes the effects of a post-growth hydrogenation on as-grown samples and device structures based on III-N-V and III-V semiconductor compounds. The spectral response of quantum wells (QWs) or superlattices (SLs) are tuned by the control dissociation of N-H complexes using a focused laser beam (photon assisted dissociation) or by thermal annealing. These approaches could be implemented in other materials and heterostructure devices, and offer the advantage of enabling an accurate control of the spectral response of a device using a layer compound with a single N- concentration. A focused laser beam is also used to diffuse hydrogen from the p-type contact layer towards the III-N-V superlattice in the intrinsic region of a p-i-n diode, thus creating preferential injection paths for the carriers and creating nanoscale light emitting diodes. Opportunities for realizing a movable micron size-light emitting diode (-LED) are also demonstrated.

Moreover, room temperature electroluminescence from semiconductor junctions formed from combinations of n-InSe, p-InSe, p-GaSe and n-In2O3 is demonstrated. These p-n junctions are fabricated using mechanical exfoliation of Bridgman-grown crystals and a simple mechanical contact method or thermal annealing. These results demonstrate the technological potential of mechanically formed heterojunctions and homojunctions of direct band gap layered GaSe and InSe compounds with an optical response over an extended wavelength range, from the near-infrared to the visible spectrum. These layered crystals could be combined in different sequences of layer stacking, thus offering exciting opportunities for new structures and devices.

Item Type: Thesis (University of Nottingham only) (PhD)
Supervisors: Patane, Amalia
Eaves, L.
Keywords: Dilute Nitrides III-N-V semiconductors, Laser writing, III-VI chalcogenide van der Waals crystals,
Subjects: Q Science > QC Physics > QC170 Atomic physics. Constitution and properties of matter
Q Science > QC Physics > QC501 Electricity and magnetism
Faculties/Schools: UK Campuses > Faculty of Science > School of Physics and Astronomy
Item ID: 50598
Depositing User: Balakrishnan, Nilanthy
Date Deposited: 19 Apr 2018 12:42
Last Modified: 20 Apr 2018 10:37

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