兼具偵測多波段紅外線及可見光的偵測器陣列模組之研發 (3/3)
Date Issued
2005-07-31
Date
2005-07-31
Author(s)
管傑雄
DOI
932215E002002
Abstract
Infrared detection has been used widely as the applications in military services,
astronomy, environmental monitoring and medicine. In recent years, many companies
and research institutes focused on the development of the infrared detector’s focal
plane array to achieve the large area and more accurate detection applications. For
quantum well or superlattice infrared photodetector, because of the selection rule, the
photodetector does not absorb radiation incident normal to the surface since the light
polarization must have an electric field component parallel to the growth direction. In
general, the single photodetector device has to be illuminated through a 45∘polished
facet. However, this illumination scheme limits the configuration of the detectors to
linear array or large focal plane array. For imaging, it is necessary to be able to couple
light uniformly to two-dimensional arrays of these detectors. In this paper, we will
present several methods to achieve the goal of coupling the normal incident light,
such as the photodetectors with V-groove structure for normal incident light coupling.
Moreover, we fabricate the one-dimension linear array based on this structure.
Besides, the periodic metal hole array is designed on the sample surface. This
structure can act as the grating and make the detector achieve the goal of normal
incidence.
V-groove structure can be fabricated on the QWIP by using anisotropic etching to
couple the normally incident light. In this paper, the efficiency for the QWIPs with
V-groove structure to couple the normally incident light is estimated by applying the
ray optics. A feasible processing procedure for fabricating the V-groove structure is
proposed. The responsivity measurement shows that the V-groove structure can
couple the normal incident light with the same efficiency as the TM mode light
incident into the 45∘edge facet of the photodetector.
For thermal imaging application, the detectors must have high background limited
performance temperature TBLIP and 1-D or 2-D (Focal Plane) detector arrays have
been used instead of the single detector. The process of the linear array fabrication is
also introduced. The experimental results show that the response of the detector array
is smaller than single device, but the dark current of detector array is much smaller
than single device. It leads to the larger detectivity of detector array. By increasing the
contact area of metal ring and tilted angle of V-grooves for larger responsivity, it will
be a new method to fabricate 1-D detector array.
For device fabrication, we can design a metal hole array with periodicity on the
sample surface. Analogous to the concept of photonic crystal, the metal hole array can
act as the grating and make the detector achieve the goal of normal incidence. The
traditional fabrication of detector with normal incidence is to thin down the substrate.Using this new structure, we can omit the thin-down process.
We fabricate three devices with different period of gratings for topside-illumination.
Base on this structure, the photoresponse of each spectral shape is tunable by the
period of gratings. The response shape is affected by surface plasmon. The plasmon
peak can be selected by period of gratings. In summary, the experimental results
confirm the applicability of SLIPs with grating structure for coupling the normal
incident light and tunable response shape by surface plasmon.
Subjects
quantum well infrared photodetector
superlattice infrared photodetector
linear array
normal incident light coupling
metal strip grating
Publisher
臺北市：國立臺灣大學電子工程學研究所
Type
report
File(s)![Thumbnail Image]()
Loading...
Name
932215E002002.pdf
Size
1.75 MB
Format
Adobe PDF
Checksum
(MD5):15213f585da7bb177cba37a0a88fb3b6