Polycrystalline III-V semiconductors with electronically passive defects may play a critical role in developing cost-effective, high-performance photovoltaics, light-emitting diodes (LEDs), lasers, and field-effect transistors (FETs). However, without effective passivation, Fermi-level pinning and undesirable Shockley-Read-Hall recombination persist, shifting developmental focus away from polycrystalline III-V and toward single-crystal III-V. Unfortunately, the high cost of these single-crystal materials and associated processing have limited their use in low-cost applications. In order to achieve low-cost, high-efficiency devices, revisiting passivation approaches for polycrystalline III-V materials may yield new commercial opportunities.
Researchers at Arizona State University have developed a novel passivation method involving deposition of an elemental, compound, or alloying material on a polycrystalline III-V thin-film. Annealing this stack through an optimized temperature-time profile results in the deposited passivation material reacting with the host polycrystalline III-V material and reducing interface states at the front interface, along the sides of the grain, and possibly passivating the back surface of the III-V grain. This modification of the III-V thin-film may reduce the number of recombination events which in turn will increase the efficiency and the overall performance of the device.
• Photovoltaic top junctions
• Flexible device substrates
• Light-emitting diodes (LEDs)
• Field-effect transistors (FETs)
Benefits and Advantages
• Effective – Preliminary treatments of optically active 1.7-eV GaInP thin-film on conductive substrate demonstrated a 210-fold improvement in photoluminescence intensity
• Enabling – Renews candidacy of polycrystalline III-V semiconductors for low-cost, high-performance devices