The Birnie Group solar class and website were created with much-appreciated support from the NSF CRCD Program under grants 0203504 and 0509886. Continuing Support from the McLaren Endowment is also greatly appreciated! Band Gap Engineering Reading the Periodic Table and Understanding Optical and Electrical Properties in Semiconductors Slides on these other topics might also be of interest (most collected during teaching years 2004 and 2005): http://www.rci.rutgers.edu/~dbirnie/solarclass/multijunctionlecture.pdf Multi Junction Solar Device Design http://www.rci.rutgers.edu/~dbirnie/solarclass/mbegrowth.pdf Molecular Beam Epitaxy http://www.rci.rutgers.edu/~dbirnie/solarclass/amorphoussi.pdf Amorphous Silicon Solar Cells http://www.rci.rutgers.edu/~dbirnie/solarclass/transparentconductors.pdf Transparent Conductors for Solar http://www.rci.rutgers.edu/~dbirnie/solarclass/arcoatings.pdf Anti Reflection Coatings for Solar http://www.rci.rutgers.edu/~dbirnie/solarclass/organicpv.pdf Organic PV http://www.rci.rutgers.edu/~dbirnie/solarclass/dssc.pdf Dye Sensitized Solar Cells http://www.rci.rutgers.edu/~dbirnie/solarclass/motorprimergatech.pdf Working with Simple DC Motors for Student Solar Projects http://www.rci.rutgers.edu/~dbirnie/solarclass/2005projectresultsindex.htm Examples of Previous Years Student Solar Projects Note: in some cases it may be possible to design custom courses that expand on the above materials (send me email!) Journal Publications of Some Recent Research: (best viewed through department home index: http://mse.rutgers.edu/dunbar_p_birnie_iii) Other Birnie Group Research: Sol-Gel Coating Quality and Defects Analysis (mostly Spin Coating): http://www.coatings.rutgers.edu Solar Research at Rutgers: Broader Overview http://www.solar.rutgers.edu Solar and Electric Vehicles System Projects (early stage emphasis) http://www.rave.rutgers.edu Professor Dunbar P. Birnie, III (dunbar.birnie@rutgers.edu) http://mse.rutgers.edu/faculty/dunbar_p_birnie
Solar Cell Design and Processing Band Gap and Association to Trends in the Periodic Table through doping and optical constant changes Dunbar P. Birnie, III dunbar.birnie@rutgers.edu Rutgers University Piscataway, NJ 08854-8065
Semiconductors Basically not insulating and also not metallic somewhere in between For many examples this comes from sp 3 hybridized covalent bonding that builds tetrahedral arrangements and very stiff and open structures Silicon and germanium are simple elemental semiconductors silicon dominates the solar market for now.
Silicon is Diamond Cubic Unit cell emphasizes the tetrahedral bonding arrangement of every Si atom: Source: http://commons.wikimedia.org/wiki/file: Diamond_Cubic-F_lattice_animation.gif
Silicon s Location in the Periodic Table Source: commons.wikimedia.org/periodic table
Doping of Silicon P-type dopants come from group III and have one fewer electron than Silicon. This is then provides an empty bonding orbital and energy level that can accept an electron from elsewhere in the structure. These elements are, therefore acceptors. N-type dopants come from group V and have one excess electron to bring to the bonding. This electron can be donated to the electronic structure. These elements are, therefore donors. Source: adapted from commons.wikimedia.org/periodic table
III-V Compound Semiconductors Requires a 1:1 Ratio of Group- III and Group V elements, bonding alternates so every III atom is surrounded by four V atoms and similarly four III s around every V. Bonding gets weaker as we move DOWN on the periodic table. Melting points and bandgaps are smaller as we move down. Example phases: GaAs, GaN, AlSb, InP, etc, etc. etc. Source: adapted from commons.wikimedia.org/periodic table
GaAs in Zinc Blende Structure Source: OCW.mit.edu
Band Gaps and Lattice Size Important for many semiconductor growth methods such as MBE and CVD, when high crystal quality is required. Source: http://web.tiscali.it/decartes/phd_html/ III-Vms-latgap.png