Nanoscopic electric potential probing: Influence of probe–sample interface on spatial resolution

Kuntze, S.B.; Sargent, Edward H.; Dixon‐Warren, St. J.; White, J.K.; Hinzer, Karin; Ban, Dayan

doi:10.1063/1.1643534

Cited by 7 publications

(1 citation statement)

References 13 publications

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“…The underlying mechanisms responsible for device failures and sub-par performance will be identified with certainty, which will not only facilitate, but accelerate device design and optimization processes. The cryogenic temperature SVM and other associated techniques 32 33 34 49 50 51 52 53 can be employed to measure important inner workings such as the device's voltage profile, dopant profile, charge carrier profile and current profile at nanometric scales and in two dimensions. It will also allow us to visualize the development and evolution of high electric field domains in not only THz QCLs, but also semiconductor superlattices and other resonant-tunneling based quantum structures, to study the extra voltage drop across THz QCLs without the top n + GaAs contact layer, and to examine whether the electron injection from the bulk contact layer into the first quantum cascade module is well aligned as expected.…”

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confidence: 99%

Direct Nanoscale Imaging of Evolving Electric Field Domains in Quantum Structures

Dhar

Razavipour

Dupont

et al. 2014

Sci Rep

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The external performance of quantum optoelectronic devices is governed by the spatial profiles of electrons and potentials within the active regions of these devices. For example, in quantum cascade lasers (QCLs), the electric field domain (EFD) hypothesis posits that the potential distribution might be simultaneously spatially nonuniform and temporally unstable. Unfortunately, there exists no prior means of probing the inner potential profile directly. Here we report the nanoscale measured electric potential distribution inside operating QCLs by using scanning voltage microscopy at a cryogenic temperature. We prove that, per the EFD hypothesis, the multi-quantum-well active region is indeed divided into multiple sections having distinctly different electric fields. The electric field across these serially-stacked quantum cascade modules does not continuously increase in proportion to gradual increases in the applied device bias, but rather hops between discrete values that are related to tunneling resonances. We also report the evolution of EFDs, finding that an incremental change in device bias leads to a hopping-style shift in the EFD boundary – the higher electric field domain expands at least one module each step at the expense of the lower field domain within the active region.

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