Uncooled Split-off Quantum Infrared Sensors for 3-5 Micron Imaging Applications
Abstract
A detector concept utilizing hole transitions from the light-hole/heavy-hole (LH/HH) band to the spin-orbit split-off (SO) band has been developed to achieve room temperature operation. The p-type GaAs/AlxGa1-xAs multiple heterojunction detectors with the threshold wavelength of 4 micrometers demonstrated uncooled operation. Investigations further showed that response extension can be realized by including hole transitions between LH and HH bands. Spectral response up to 16.5 micrometers operating up to a temperature of 330 K has been obtained, where the LH-HH response is superimposed on the free-carrier response. Analysis on the dark current mechanisms was carried out on these high-operating-temperature split-off detectors in order to improve electrical uniformity. Further optimization using graded barriers with an offset between the barriers on the two sides of an emitter was explored as a method of reducing the capture rate of photocarriers in the emitters. Experiments showed that responsivity increased by a factor of 10 or more was measured in graded-barrier detectors in comparison with detectors without the graded barrier. The graded barrier structure is also shown to be capable of operating in photovoltaic model and a good candidate for high-temperature photovoltaic detectors.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 20, 2012
- Accession Number
- ADA584437
Entities
People
- A. G. Perera
- Y. Lao
Organizations
- Georgia State University