Rational design of monocrystalline (InP)(y)Ge(5-2y)/Ge/Si(100) semiconductors: synthesis and optical properties

Area of Science:

• Materials Science
• Solid-State Chemistry
• Semiconductor Physics

Background:

• Previous work established a strategy for synthesizing functional, crystalline Si(5-2y)(AlX)y semiconductors.
• There is a need for new semiconductor materials with tunable properties for advanced electronic and optoelectronic devices.

Purpose of the Study:

• To extend semiconductor synthesis strategies to a new class of germanium-III-V hybrid compounds.
• To create and characterize (InP)(y)Ge(5-2y) alloys with potential optoelectronic applications.

Main Methods:

• Gas source molecular beam epitaxy (MBE) growth on Ge-buffered Si(100) substrates.
• Controlled interaction between P(GeH3)3 precursors and In atoms to form "In-P-Ge3" building blocks.
• Characterization using high-resolution X-ray diffraction (XRD), XTEM, EDX, RBS, Raman spectroscopy, and ellipsometry.
• Ab initio density functional theory (DFT) simulations for structural and bonding analysis.

Main Results:

• Successfully synthesized monocrystalline (InP)(y)Ge(5-2y) alloys (y = 0.3-0.7) that are tetragonally strained and coherent with the Si substrate.
• The alloys possess a cubic diamond-like structure, assembled from "In-P-Ge3" molecular building blocks.
• Controlled Ge enrichment was achieved by adjusting deposition conditions, influencing the Ge content relative to InPGe3.
• DFT simulations validated the proposed crystal structure and building-block assembly, accurately predicting lattice constant variations.

Conclusions:

• The study demonstrates a novel method for creating germanium-III-V hybrid semiconductors using molecular building blocks.
• The synthesized (InP)(y)Ge(5-2y) alloys exhibit promising structural and electronic properties.
• Observed photoluminescence suggests significant potential for optoelectronic device applications.