Table 2.

Features of various in situ techniques for investigating the switching mechanism

In situ technique	Spatial scale	Temporal scale	Sample type	Information
In situ TEM100	Å ~ μm	μs ~ hours	Vertical structure Lateral structure Tip-based structure	Filament morphology Chemical distribution Electronic structure IV measurement
In situ STXM26,51	nm ~ μm	ms ~ hours	Vertical structure	Elemental distribution Chemical state IV measurement
In situ EBIC52	10 nm ~ 10 μm	ms ~ mins	Vertical structure Lateral structure	Distribution of electric field IV measurement
In situ STM30	nm ~ 100 nm	100 ms ~ days	Tip-based structure	Local electron density IV measurement Cycling
In situ CAFM42	10 nm ~ 10 μm,	100 ms ~ days	Tip-based structure	Electrochemical reactions IV measurement Cycling
In situ cyclic voltammetry57,58	Å ~ 100 nm	10 ms ~ days	Vertical structure	Electrochemical kinetics Diffusion activity
In situ optical microscopy56	100 nm ~ 10 μm	s ~ hours	Lateral structure	Filament morphology Electrochemical reactions