Extracting the effective bandgap of heterojunctions using Esaki diode I-V measurements

Abstract

The effective bandgap is a crucial design parameter of heterojunction tunneling field-effect transistors. In this letter, we demonstrate a method to measure the effective bandgap directly from the band-to-band tunneling current of a heterojunction Esaki diode, of which we only require knowledge of the electrostatic potential profile. The method is based on a characteristic exponentially increasing current with forward bias, caused by sharp energy filtering at cryogenic temperature. We apply this method experimentally to a n+In0.53Ga0.47As/pGaAs0.5Sb0.5 Esaki diode and define requirements to apply it to other heterojunctions.

Broken-gap energy alignment in two-dimensional van der Waals heterostructures for multifunctional tunnel diodes

“…While these materials were calculated to have a non-zero band gap, previous experimental analysis of the InGaAs/GaAsSb type-III broken-gap heterostructure, measured the effective bandgap of the heterojunction to be B0.21 eV (or 210 meV). 45 Given that quantum tunnelling is the conduction mechanism in this system, and that this band gap value is similar to the band gap values we calculated for the 1T-HfS 2 /WTe 2 , TiS 2 /WSe 2 , and TiS 2 /ZnO heterostructures, it is possible they may also exhibit quantum tunnelling properties under load.…”

Band-to-Band Tunneling-Dominated Thermo-Enhanced Field Electron Emission from p-Si/ZnO Nanoemitters

“…In the following discussions, we take I t = I for exploring the applicability of the model. The band-to-band tunneling could be approximated by an electron penetrating a triangular potential barrier, with a width related to the electric field at the depletion region and a height related to the effective band gap ( E eff ) . As indicated in the band diagram shown in the inset of Figure c, the effective band gap at the interface of the heterojunction is defined as E eff = E c/n‑ZnO – E v/p‑Si with E c/n‑ZnO being the n-doped region conduction band edge and E v/p‑Si the p-doped region valence band edge.…”

“…The band-to-band tunneling could be approximated by an electron penetrating a triangular potential barrier, 37 with a width related to the electric field at the depletion region and a height related to the effective band gap (E eff ). 38…”

In-plane InGaAs/Ga(As)Sb nanowire based tunnel junctions grown by selective area molecular beam epitaxy

“…The J-V characteristics measured for single NW devices from sample B exhibit different evolutions with respect to the width of the mask openings (figures 12(a) and (b)). First of all, owing to the larger effective band gap at the InGaAs/ GaAsSb interface [12], the current density is reduced with respect to sample A. In addition, the peak to valley current ratio (PVCR) can be as large as 3 for the widest [1-10]oriented devices and for the narrowest [110]-oriented devices (figures 12(c) and (d)).…”