Deep UV emitters and polariton lasers (Research topic area 4.2 Optoelectronics)
Abstract
The overall objectives of this project are to investigate the optical and exciton-polariton properties in 2D layer-structured wide bandgap h-BN semiconductor and related quantum wells (QWs) and to explore the feasibility of achieving deep UV emitters and polariton lasers based on h-BN. Due to its extraordinary physical properties, hexagonal boron nitride (h-BN) with a bandgap of about 6.5 eV has been shown to possess rich novel properties partly due to its layered-structure induced quasi-2D nature and has the potential to outperform AlN which is the presently best known deep UV semiconductor. The demonstrated unique features of h-BN in comparison with AlN include: (1) Higher band edge emission intensity than AlN; (2) Higher p-type conductivity than AlN; and (3) Preferred optical emission polarization properties over AlN. Moreover, the exciton binding energy of 740 meV in h-BN is at least one order of magnitude larger than those in other well-known wide band gap semiconductors, GaN, ZnO, and AlN. This together with the naturally occurring large quantum confinement induced by the layered-structure may significantly enhance the exciton oscillator strength, collective dipole interaction between the excitons and photon fields and hence the Rabi splitting energy. Therefore, h-BN appears to be the most attractive material system to study the optical properties of deep UV emitters and room temperature polariton lasers in inorganic semiconductors. To accomplish the proposed objectives, the following technical approaches will be pursued: ¥ Further develop metal organic chemical vapor deposition epitaxial growth and doping processes to obtain high quality h-BN based QWs to lay the foundation for realizing current injection deep UV light emitting devices with operating wavelengths down to .220 nm; ¥ Fabricate h-BN QW microcavity structures with strong confinement of the exciton-photon modes and to allow the investigation of deep UV exciton-polariton optical and lasing properties; ¥ Study the polariton dispersion and its evolution with dimensionality in h-BN QW microcavities; ¥ Compare the optical and lasing properties of conventional laser structures with those of h-BN microcavity polariton laser structures to reveal the unique features of polariotn lasers based on layer-structured wide bandgap semiconductors. The proposed efforts would not only yield breakthroughs in methods for the fabrication of deep UV emitters with novel properties, but would also lead to technological advancements in novel deep UV photonic materials and devices for applications including highly compact deep UV (wavelength down to 220 nm) light sources and detectors for probing intrinsic fluorescence in proteins, medical research, deep UV sensing and photocatalysis. The results will broadly impact areas in energy, medical, security, communication, and entertainment. Through the involvements in research, the program will train students in the areas of novel semiconductor materials synthesize, nano-fabrication techniques, material/device design and processing, and optical and optoelectronic properties characterization using the state-of-the-art experimental facilities.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jan 12, 2017
- Source ID
- W911NF1610268
Entities
People
- Hongxing Jiang
Organizations
- Army Contracting Command
- Texas Tech University
- United States Army