Abstract

State of the art triple junction solar cells have achieved in excess of 43% efficiency. In order to extend this beyond a multijunction-only design, novel approaches to photon conversion must be sought and realized. Two novel mechanisms, bandgap engineering and absorption from an intermediate state within a semiconductor bandgap show promise in this regard. A single promising approach to both of these novel mechanisms is to exploit the unique properties of nanostructured materials to extend the absorption spectrum for the ultimate improvement of solar energy conversion efficiency. In this work, it is proposed to utilize InAs quantum dot (QD) nanostructures embedded in a GaAs p-i-n solar cell device to investigate the effects of these unique properties. Theoretical and experimental approaches will be used in tandem to explore these types of devices with special attention given to mechanical issues and optical processes inherent in this type of device. In this work, typical optical, mechanical and photovoltaic experiments for these devices will be demonstrated. The techniques and analysis used here can lead to the advancement of the use nanostructures in solar cells as well as many other types of optoelectronic devices. As a result, an improved method of strain balancing (SB) three-dimensional layers is developed and implemented in QD solar cells. Along with this improved technique, a reduced InAs coverage value was found to ultimately improve the device absolute power conversion efficiency by 0.5%.

Library of Congress Subject Headings

Quantum dots--Optical properties; Quantum dots--Mechanical properties; Photovoltaic cells--Design and construction; Nanoelectromechanical systems--Design and construction; Solar cells--Materials

Publication Date

1-2012

Document Type

Dissertation

Student Type

Graduate

Degree Name

Microsystems Engineering (Ph.D.)

Department, Program, or Center

Microsystems Engineering (KGCOE)

Advisor

Ryne P. Raffaelle

Advisor/Committee Member

Seth Hubbard

Advisor/Committee Member

Bruce W. Smith

Comments

Physical copy available from RIT's Wallace Library at QC611.6.Q35 B34 2012

Campus

RIT – Main Campus

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