Magnetic Field Effects on InSb Tunnel Diodes

For InSb tunnel diodes placed in a magnetic field H, the ratio of longitudinal to transverse tunnel currents yields a relatively direct measurement of the tunneling exponential λ (V). For a typical InSb diode we found λ0, the zero bias value of λ, to be 10.7±0.2, which implies an effective built-in junction field of 5.7±0.1×104 v/cm. This value agrees well with the maximum and average junction fields calculated using the known doping concentrations and assuming a step junction. The pre-exponential tunneling factor is found to be (1.8±0.4)×107 amp/v cm2, which is about 30 times larger than Kane's theoretical result. The voltage dependence of λ is found to be expressible as λ=λ0(1−V/V0)−1/n with V0=0.2 ev and n=2.2.