Crystal Phase Control and Room-Temperature Random Lasing in Multiperiod GaAs/AlGaAs Axial Heterostructure Nanowires...

Area of Science:

• Materials Science
• Nanotechnology
• Optoelectronics

Background:

• Semiconductor axial heterostructure nanowires (NWs) are promising for nanophotonics.
• Challenges exist in achieving crystal phase uniformity, impacting optoelectronic performance.
• Nucleation instability during growth is a key limiting factor.

Purpose of the Study:

• To demonstrate Al-mediated catalyst engineering for crystal phase control in GaAs/AlGaAs NWs.
• To investigate the effect of varying GaAs growth times on NW morphology and phase.
• To achieve efficient random lasing in engineered NWs.

Main Methods:

• Fabrication of multiperiod GaAs/Al0.4Ga0.6As axial heterostructure NWs using molecular beam epitaxy.
• Systematic variation of GaAs segment growth times (30, 60, 90, 120 s).
• Analysis of NW morphology and crystal phase using advanced characterization techniques.
• Optical characterization to assess random lasing performance.

Main Results:

• All fabricated NWs exhibited a lotus-root morphology.
• The 90 s GaAs growth time sample (GaAs-90) achieved quasi-pure zincblende (ZB) phase formation.
• Al incorporation stabilized ZB nucleation by reducing Ga droplet size and surface energy.
• GaAs-90 demonstrated room-temperature random lasing with a threshold of 55.59 mW/cm².

Conclusions:

• Al-mediated catalyst engineering is an effective strategy for controlling crystal phase in NWs.
• Precise control over crystal phase is crucial for efficient NW random lasing.
• This work provides a scalable framework for on-chip integrated photonics using engineered NWs.