Complex crystallization dynamics in amorphous germanium observed with dynamic transmission electron microscopy

Abstract

Crystallization of amorphous germanium (a-Ge) by laser or electron beam heating is a remarkably complex process that involves several distinct modes of crystal growth and the development of intricate microstructural patterns on the nanosecond to ten microsecond timescales. Here we use dynamic transmission electron microscopy (DTEM) to study the fast, complex crystallization dynamics with 10 nm spatial and 15 ns temporal resolution. We have obtained time-resolved real-space images of nanosecond laser-induced crystallization in a-Ge with unprecedentedly high spatial resolution. Direct visualisation of the crystallization front allows for time-resolved snapshots of the initiation and roughening of the dendrites on sub-microsecond timescales. This growth is followed by a rapid transition to a ledge-like growth mechanism that produces a layered microstructure on a timescale of several microseconds. This study provides new insights into the mechanisms governing this complex crystallization process and is a dramatic demonstration of the power of DTEM for studying time-dependent material processes far from equilibrium.

In situ tuning of crystallization pathways by electron beam irradiation and heating in amorphous bismuth ferrite films

“…S2 †), which illustrates that the nanoparticles are Bi-enriched while Fe and O are driven to the boundaries between nanoparticles. ) could lead to the occurrence of explosive crystallization, 18,19 in which a very large, triangular-like nanoparticle is formed with $60 nm sides.…”

Взрывной Переход В Аморфном Микропроводе

“…Большую роль при этом играла подложка, в которую осуществлялся основной отвод тепла, выделяющегося при саморазогреве. Образцы в виде аморфных пленок удобны для исследований, так как они позволяют на-блюдать за процессом превращения, используя различ-ные микроскопы [5,10,11]. Пространственные масштабы там вполне макроскопические (миллиметры, сантимет-ры).…”

Thermal crystallization of sputter-deposited amorphous Ge films: Competition of diamond cubic and hexagonal phases

“…Another interesting feature in crystallization of a-Ge films has been recognized: 24,25 crystallization occurs explosively by laser annealing and the microstructure is inhomogeneous radically in the irradiated zone. Takamori et al 24 interpreted that amorphous structure is inhomogeneous and strain-induced mechanism is operative.…”