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Title: Theoretical investigation of carrier transport and optical properties in dilute nitrides
Author: Vogiatzis, Nikolaos
ISNI:       0000 0004 2725 2363
Awarding Body: University of Bristol
Current Institution: University of Bristol
Date of Award: 2010
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Scope of this thesis is to understand how the incorporation of ni trogcn in stan- dard III- V alloys affects the electronic ham] structure, the optical gain and the carrier transport properties. Following the band anticrossing model, two nitrogen impurity en- vironmonts have been used to calculate the material gain of the comprcssivclv strained Gal_xlnx:.'\yAsl_y/GaAs quantum well (Q\V) system, using a reduced density of states for the:"-"" pairs. using it generalized Andcrson impurity model and Green's functions we have derived complex cigonvalucs of the system and compared it versus the anti-crossing model. Analytical expressions for the broadening and the energy shift have been extracted. using these quantities CLe; inpu t.s, t.he mixed density of states (DOS) have been obtained. The latter arc then used in the calculation of the scattering rates. Electron-defect and electron phonon scattering processes have been considered in bulk and quantum wells. For the latter two models of infinite square and triangular Q\V have been used. Polar optical phonon (POP) scattering and scattering associated with nitrogen arc found 1:0 be dominant. A single Monte Carlo code uses these scattering rates to derive the field-velocity dependence. We find a characteristic NDR bchavior which is strongly dependent on the electron effective mass, the nitrogen concentration, the number of the localized impurity states and their relative energy position.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available