Growth of novel InAs sources and detectors
Abstract
The mid-infrared (MIR) fingerprint region of the electromagnetic spectrum (3-30 ?m) is of great importance for chemical sensing. Optoelectronics in this range have been made possible through unipolar intersubband (ISB) emitters and detectors. The quantum cascade laser (QCL) and detectors (QCD) use bandgap engineering, e.g., conduction band offset (CBO), to design the energy levels, carrier lifetimes, and optical transitions. The QCD is the complimentary detector to the QCL, where the optical transition is between two bound states and the carriers scatter to neighboring wells and cascade to the ground state of the next cascade. The QCD can be optimized for robustness, using diagonal or multiple transitions, tuned to match the wavelength of a QCL, do not saturate under QCL illumination, they work at and above room temperature, and are intrinsically fast due to the picosecond lifetimes. Low carrier effective mass in the well increases the gain in lasers, the total absorption in detectors, and reduces the noise behavior, by reducing the ISB scattering, therefore InAs is a desirable candidate due to its very low electron effective mass 0.023m0. To utilize InAs quantum wells grown by molecular beam epitaxy, strain compensated AlSb barriers have been used to realize a 2.6 ?m (0.48 eV) QCLs. However, ISB active regions are 3-30 ?m thick with thousands of layers where strain compensation and growth interruptions are time intensive and can result in a 30% fluctuation in alloy composition. The latticematched InAs/AlAsSb system (2.1 eV) is a good alternative for QCDs. In this seedling effort, we propose to investigate lattice-matched InAs/AlAsSb MIR QCDs to develop the growth of this new material system and improve the active region design. This InAs-based QCD has the potential for a high speed and efficient room temperature photodetector that can cover a broader range of wavelengths than other material systems.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Sep 11, 2017
- Source ID
- FA95501710340
Entities
People
- Max Andrews
Organizations
- Air Force Office of Scientific Research
- TU Wien
- United States Air Force