Interface roughness and polar optical phonon scattering in RTDs

Abstract

The contributions of interface roughness scattering and polar optical phonon scattering to the valley current of In 0.53 Ga 0.47 As/AlAs/InAs resonant tunnelling diodes (RTDs) are theoretically found to be comparable. An In 0.53 Ga 0.47 As/AlAs/InAs RTD design is suggested to experimentally observe the phonon peak which has never been observed in this material system. Such a device will provide a calibration point for the theoretical calculations.

Strong wavevector dependence of hole transport in heterostructures

“…Electron states are occupied close to the point and the bands can typically be assumed to be isotropic. † For high current density devices operated at room temperature the effects of incoherent scattering inside the central RTD region [5,[8][9][10] have been shown to be negligible while bandstructure effects such an nonparabolicity and complex band wrapping are dominant [5][6][7]. In such a case the current can be computed [2,7] using an expression of the form…”

“…This conduction channel is finally shut off as the bulk (3D) HH emitter dispersion is below the Fermi energy and cannot supply any more carriers at a transverse momentum of about k ≈ 0.027. Figure 10D shows the momentum dependence of the resonance linewidths of HH2 that is needed for the evaluation of eqn (9). The HH1 ↑ shows an interesting large (three orders of magnitude) dependence of the resonance linewidth.…”

Advancing nanoelectronic device modeling through peta-scale computing and deployment on nanoHUB

“…NEMO 1-D also employs a Hartree self consistent quantum mechanical charge calculation in both the contacts and the central body of an RTD. Realistic band structures, with non-parabolic regions and band warping, are also included in NEMO 1-D, along with low temperature scattering due to optical phonons, acoustical phonons, and interface roughness [43][44][45]. Incorporating this level of accuracy is demanding, and this mature code is the standard to which the others are compared.…”

Valley current characterization of high current density resonant tunnelling diodes for terahertz-wave applications

“…These mechanisms have previously been investigated both theoretically and experimentally for Si/SiGe, AlGaAs/GaAs, and AlSb-InAs RTDs, 15,16 but no detailed experimental analysis has been reported yet for high current density InGaAs/AlAs/InP RTDs. 17,18 In this paper, we report an experimental analysis on the valley current of a high current density double barrier InGaAs/AlAs/InP RTDs grown by metal-organic vapour phase epitaxy (MOVPE), with a view to maximize P MAX at THz frequencies, and hence the maximum operating frequency. We propose and demonstrate a methodology to investigate the origin of the valley current of a high J RTD by measuring the surface leakage current of the device and the temperature dependence of the valley current.…”