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Indirect Bandgap‐Like Current Flow in Direct Bandgap Electron Resonant Tunneling Diodes
Author(s) -
Klimeck Gerhard
Publication year - 2001
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/1521-3951(200107)226:1<9::aid-pssb9>3.0.co;2-y
Subject(s) - common emitter , quantum tunnelling , physics , diode , electron , condensed matter physics , quasi fermi level , effective mass (spring–mass system) , transverse plane , fermi level , current (fluid) , resonant tunneling diode , band gap , optoelectronics , direct and indirect band gaps , quantum well , optics , quantum mechanics , structural engineering , engineering , thermodynamics , laser
The current turn‐on and turn‐off in a resonant tunneling diode (RTD) is determined by the crossing of the central resonance subband with the Fermi level in the emitter, the subbands of quasi‐bound states in the emitter and the conduction band edge in the emitter. In a typical RTD the subbands in the central well and the emitter are similar, resulting in a simple resonant current flow for almost all transverse momenta. Since most of the electrons have zero transverse momentum, one therefore observes that most of the carriers travel straight through the structure. This paper presents a mechanism that can generate off‐zone‐center current flow in electron resonant tunneling diodes, where most of the carriers travel through the structure at an angle for a certain bias range. The basic idea is that if the effective mass in the RTD well is much smaller than the effective mass in the emitter, subband crossings will occur outside the zone center, resulting in this unintuitive distribution of the current as a function of transverse momentum. This mechanism is shown to increase the valley current within a single band approximation without non‐parabolicity.