In this presentation, I have talked about how carbon-dioxide emission by human activities is responsible for climate change and it can affect our planet. I have also talked about how Earth has a natural thermostat for maintaining its temperature and how life on Earth has survived through those temperature variations.In the end, I have talked about how new emerging technology in power electronics can help to mitigate the problem

2. Part – A
Climate Change

40. Part – B
The Emerging Technology

41. Wide Band Gap Semiconductors
Gallium Nitride
Silicon Carbide
Diamond

42. What is Band Gap and Why it Matters?
• Band Gap is the energy required to excite an electron from the
valence band to the conduction band.
• If band gap is large then a higher critical electric field is required
to initiate impact ionization, thus causing avalanche breakdown.
• So the device will have high reverse voltage withstanding
capability.
Breakdown Voltage ˆ= 1/2 * (Drift Width) * (Critical Electric Field)
• For same breakdown voltage, WBG device will be smaller.
• Due to large band energy high temperature is required to cause
ionization, so high temperature operation possible

43. Why WBG Semiconductor Devices?
• Lower on-resistance
• Faster switching speeds and lower switching losses
• Higher operating temperatures
• Better thermal conductivity
• Smaller size
• Lower cost
• Highly reliable and durable
• High voltage blocking capability

44. Parameter Comparison
Parameter Units Silicon GaN SiC
Band Gap, Eg eV 1.12 3.39 3.26
Critical Field, ECrit
MV/cm 0.23 3.3 2.2
Electron Mobility, μn cm2/V.s 1400 1500 950
Permittivity, εr _ 11.8 9 9.7
Thermal Conductivity, λ W/cm.K 1.5 1.3 3.8

48. Aspect of Energy Saving
and Carbon Footprint
1. The impact of Wide Band Gap Semiconductor based power
electronics on energy savings can be simply predicted by the
energy saving record of IGBT Technology in America till date
which is 15 Trillion Dollars which is equivalent to 15 lakh crore
rupees.
2. The cumulative impact of IGBT technology in 20 years has
reduced CO2 emissions by 2 Trillion Pounds which is the total CO2
emission by the world in 2 years.

50. WBG Inverters convert DC to AC while reducing the losses by 50%

52. Widee Band Gap Inverters Convert DC to Sc
POWER TRAIN OF TESLA’S ELECTRIC CAR

55. WBG based LEDs produce
10 times more light and lasts 30 times longer
Expected to save 250 Billion $ by 2030

57. High Voltage
DC Transmission

60. References
• Wide Bandgap semiconductors factsheet energy.gov
• The scale-up of wide bandgap power semiconductor
technology and power energy.gov
• Gallium nitride substrates factsheet
• IEEE power electronics magazine vol 2, no. 1 super power
devices
• IEEE power electronics magazine vol 2, no. 2 super power
devices
• Oak Ridge National Laboratory

61. THANK YOU