Electrical Engineering
      and Computer Sciences

Electrical Engineering and Computer Sciences

COLLEGE OF ENGINEERING

UC Berkeley

Band-Edge Steepness Obtained from Esaki/Backward Diode Current-Voltage Characteristics

Sapan Agarwal and Eli Yablonovitch

EECS Department
University of California, Berkeley
Technical Report No. UCB/EECS-2013-245
December 31, 2013

http://www.eecs.berkeley.edu/Pubs/TechRpts/2013/EECS-2013-245.pdf

While science has good knowledge of semiconductor bandgaps, there is not much information regarding the steepness of the band-edges. We find that a plot of absolute conductance, I/V versus voltage, V, in an Esaki diode or a backward diode will reveal a best limit for the band tails, defined by the tunneling joint density of states of the two band-edges. This joint density of states will give information about the prospective subthreshold swing voltage that could be expected in a tunneling field effect transistor. To date, published I-V characteristics indicate that the joint band-tail density of states is not steep enough to achieve less than 60mV/decade. Heavy doping inhomogeneity, among other inhomogeneities, result in a gradual density of states extending into the band gap. The steepest measured tunnel diodes have had a tunneling joint density of states greater than 90mV/decade.


BibTeX citation:

@techreport{Agarwal:EECS-2013-245,
    Author = {Agarwal, Sapan and Yablonovitch, Eli},
    Title = {Band-Edge Steepness Obtained from Esaki/Backward Diode Current-Voltage Characteristics},
    Institution = {EECS Department, University of California, Berkeley},
    Year = {2013},
    Month = {Dec},
    URL = {http://www.eecs.berkeley.edu/Pubs/TechRpts/2013/EECS-2013-245.html},
    Number = {UCB/EECS-2013-245},
    Abstract = {While science has good knowledge of semiconductor bandgaps, there is not much information regarding the steepness of the band-edges. We find that a plot of absolute conductance, I/V versus voltage, V, in an Esaki diode or a backward diode will reveal a best limit for the band tails, defined by the tunneling joint density of states of the two band-edges. This joint density of states will give information about the prospective subthreshold swing voltage that could be expected in a tunneling field effect transistor. To date, published I-V characteristics indicate that the joint band-tail density of states is not steep enough to achieve less than 60mV/decade. Heavy doping inhomogeneity, among other inhomogeneities, result in a gradual density of states extending into the band gap. The steepest measured tunnel diodes have had a tunneling joint density of states greater than 90mV/decade.}
}

EndNote citation:

%0 Report
%A Agarwal, Sapan
%A Yablonovitch, Eli
%T Band-Edge Steepness Obtained from Esaki/Backward Diode Current-Voltage Characteristics
%I EECS Department, University of California, Berkeley
%D 2013
%8 December 31
%@ UCB/EECS-2013-245
%U http://www.eecs.berkeley.edu/Pubs/TechRpts/2013/EECS-2013-245.html
%F Agarwal:EECS-2013-245