Graphene Synthesis and Interface Engineering for Graphene/Silicon Schottky Junction Solar Cells

  • Aaesha Abdulla Alnuaimi

Student thesis: Doctoral Thesis

Abstract

With the rapid growth in world population and economic development, the world energy requirement is growing. Conventional energy resources based on the fossil fuels are limited and cause environmental pollution. Such concerns have increased the efforts towards the utilization of renewable energy to provide security for future development and growth. One of the most abundant and rapidly growing renewable energy resources is solar energy. Among the different technologies to utilize solar energy is Photovoltaics (PV) solar cells. The current efforts in PV research are mainly focused on developing low cost and high efficiency solar cells through the investigation of new materials. Among these materials, graphene has attracted great attention in the PV community due to its excellent electronics and optical properties. The combination of the high electrical conductivity and optical transmittance makes graphene a promising candidate as a low cost, transparent conductive-electrode for optoelectronics devices including PV cells. The formation of Schottky junction between graphene (Gr) and n-type silicon (Si) has resulted in the development of Gr/Si Schottky barrier solar cells (SBSC). The first reported power conversion efficiency (PCE) of Gr/Si SBSC was 1.65% in 2010 and it reached 15.6% within five years. However, these solar cells still suffer from instability issue due to the growth of native oxide at the interface between graphene and silicon. In addition, the performance of Gr/Si SBSC is highly affected by the recombination of the charge carriers at the interface. Among the different approaches to reduce the charge recombination and improve the performance of Gr/Si SBSC is engineering the interface between Gr and Si through the use of interfacial layers. Interfacial layers play a key role in suppressing the charge recombination at the interface and improving the open circuit voltage of the cell. In this dissertation, the effect of different metal oxide interfacial layers on the performance of Gr/Si SBSC has been investigated through simulations and experiments. For simulation, a technology computer aided design (TCAD) model has been developed to study the impact of key materials parameters with the aim of optimizing the interfacial layers and to obtain phenomenological understanding on the experimental observation. Furthermore, to study Gr/Si SBSC experimentally, a high quality monolayer graphene has been synthesized using chemical vapor deposition (CVD) and the interfacial layer optimization has been done using atomic layer deposition (ALD). With the use of interfacial layers, both simulation and experimental results have shown an improvement in the solar cell performance and stability. The results of this work show a new route for fabricating efficient and stable Gr/Si SBSC.
Date of AwardMay 2017
Original languageAmerican English
SupervisorAmmar Nayfeh (Supervisor)

Keywords

  • Graphene Synthesis
  • Interface Engineering
  • Solar Cells
  • World Energy Requirements
  • Energy Resources – Renewable energy – Solar energy – Graphene – Optoelectronics devices
  • Power Conversion Efficiency
  • Computer Aided Design
  • Interfacial Layers.

Cite this

'