Persistent optical phenomena in oxide semiconductors
- Washington State University, Pullman, WA (United States)
The interaction of transparent oxide semiconductors with light is critically important for a range of applications. Persistent effects could be exploited for holographic memory or optically defined circuits. Conversely, they may also be detrimental to device operation. Large, room-temperature persistent photoconductivity (PPC) was discovered in strontium titanate (SrTiO3, STO) after annealing in a hydrogen-containing atmosphere. Barium titanate (BaTiO3, BTO), a ferroelectric material, was recently found to also exhibit PPC. Room-temperature photodarkening was observed in Cu-doped gallium oxide (β-Ga2O3) after exposure to sub-bandgap light. Hydrogen is believed to play a central role in these persistent phenomena. In the proposed model, a photon excites substitutional hydrogen (a proton inside an oxygen vacancy), making the defect unstable. The proton leaves and binds to a host oxygen atom, forming an O-H bond that is observed with infrared spectroscopy. Here, an oxygen vacancy is left behind. Because oxygen vacancies in STO and BTO are shallow donors, this process results in PPC. In β-Ga2O3:Cu, however, the oxygen vacancy neighbors a Cu acceptor. In that case, photoexcitation results in the rare Cu3+ state, which absorbs visible light. The effect can be “erased” by annealing at 300-400°C.
- Research Organization:
- Washington State Univ., Pullman, WA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES). Materials Sciences & Engineering Division (MSE); National Science Foundation (NSF); US Air Force Office of Scientific Research (AFOSR)
- DOE Contract Number:
- FG02-07ER46386; DMR-2109334; FA9550-18-1-0507
- OSTI ID:
- 2315027
- Journal Information:
- Oxide-based Materials and Devices XIV, Vol. 12422; Conference: SPIE OPTO, San Francisco, CA (United States), 28 Jan - 3 Feb 2023
- Country of Publication:
- United States
- Language:
- English
Theory of the Atomic and Electronic Structure of DX Centers in GaAs and Al x Ga 1 − x As Alloys
|
August 1988 | |
Deep donor levels ( D X centers) in III‐V semiconductors
|
February 1990 | |
SrTi O 3 : An intrinsic quantum paraelectric below 4 K
|
April 1979 | |
Dopants and Defects in Semiconductors
|
February 2018 |
Similar Records
Persistent Room-Temperature Photodarkening in Cu-Doped
Giant persistent photoconductivity in BaTiO{sub 3}/TiO{sub 2} heterostructures