Growth and structural characteristics of metastable β-In₂Se₃ thin films on H-terminated Si(111) substrates by molecular beam epitaxy*

Abstract

Epitaxial growth and structural characteristics of metastable β-In2Se3 thin films on H-terminated Si(111) substrates are studied. The In2Se3 thin films grown below the β-to-α phase transition temperature (453 K) are characterized to be strained β-In2Se3 mixed with significant γ-In2Se3 phases. The pure-phased single-crystalline β-In2Se3 can be reproducibly achieved by in situ annealing the as-deposited poly-crystalline In2Se3 within the phase equilibrium temperature window of β-In2Se3. It is suggeted that the observed γ-to-β phase transition triggered by quite a low annealing temperature should be a rather lowered phase transition barrier of the epitaxy-stabilized In2Se3 thin-film system at a state far from thermodynamic equilibrium.

Low-Dimensional In2Se3Compounds: From Material Preparations to Device Applications

“…Recently, the growth of β-In 2 Se 3 films by MBE was reported by Shen et al . First, a H-passivated Si(111) substrate was prepared.…”

“…However, it is still challenging to prepare single-phase and single-crystal αor β-In 2 Se 3 using MBE under the nonequilibrium thermodynamics without following annealing processes. Recently, the growth of β-In 2 Se 3 films by MBE was reported by Shen et al 124 First, a H-passivated Si(111) substrate was prepared. Second, the substrate was degassed at 453 K for 12 h. Third, appropriate temperatures of Se and In sources were set to achieve the flow ratio of ∼15:1 of Se/In.…”

Monolithic epitaxy and optoelectronic properties of single-crystalline γ-In2Se3 thin films on mica*

“…During the deposition, the Se/In beam equivalent pressure ratio was fixed at 20:1 to create a Se-rich environment. [21,23] At In BEP of ∼ 1 × 10 −7 mbar, which corresponds to a QCO rate of ∼ 2 monolayers (MLs) In on γ-In 2 Se 3 (0 0 1) surface per minute, a growth rate of ∼ 1 nm (approximately a half unit cell length in c-axis of γ-In 2 Se 3 ) per minute of γ-In 2 Se 3 film was achieved as further evidenced by ex situ thickness inspection by a profilometer. Noting that one unit cell of γ-In 2 Se 3 consists of 4 MLs In along c-axis, we thereby deduced thorough surface incorporation of In adatoms during epitaxial growth of γ-In 2 Se 3 .…”

Vertical MBE growth of Si fins on sub-10 nm patterned substrate for high-performance FinFET technology*

“…However, the traditional catalytic growth suffers from metal contaminations and imprecise positioning, so it is not suitable for large-scale integration. [9][10][11][12][13][14][15][16] Other researchers have also studied the molecular beam epitaxy (MBE) growth of nanowires on a non-patterned substrate, but the control of size and position is quite difficult. [17][18][19][20][21][22][23][24][25][26][27][28] Recently, some experiments on MBE growth have been conducted on 30-nm scale patterned Si templates.…”