Detailed study of above bandgap optical absorption in HgCdTe

被引:49
作者
Moazzami, K [1 ]
Phillips, J
Lee, D
Krishnamurthy, S
Benoit, G
Fink, Y
Tiwald, T
机构
[1] Univ Michigan, Dept Elect Engn & Comp Sci, Ann Arbor, MI 48109 USA
[2] Rockwell Sci Co, Camarillo, CA 93012 USA
[3] SRI Int, Menlo Pk, CA 94025 USA
[4] MIT, Dept Mat Sci & Engn, Cambridge, MA 02139 USA
[5] JA Woollam Co Inc, Lincoln, NE 68508 USA
关键词
HgCdTe; optical absorption coefficient; infrared (IR) detector; transmission; spectroscopic ellipsometry;
D O I
10.1007/s11664-005-0019-3
中图分类号
TM [电工技术]; TN [电子技术、通信技术];
学科分类号
0808 ; 0809 ;
摘要
HgCdTe remains the material of choice for high-performance infrared (IR) detectors due to its tunable direct bandgap energy corresponding to the IR spectral region, and the advancement of HgCdTe materials growth and processing technologies. Accurate knowledge of the HgCdTe optical absorption coefficient is important for IR detector design, layer screening, and device analysis. The spectral response for IR detectors is dependent on optical absorption above the bandgap energy, where much of the study of absorption coefficient in HgCdTe has focused on the bandtail region. In this work, the optical absorption coefficient was studied by theoretical bandstructure calculations and experimental measurements on HgCdTe layers using techniques of IR spectroscopic ellipsometry and IR transmission. The theoretical and experimental results suggest that the absorption coefficient between 600 cm(-1) and 5,000 cm(-1) is related to energy relative to bandgap with a fractional exponent between 0.6 and 1, rather than the previously used expressions relating to a parabolic or hyperbolic bandstructure. The fitting parameters for Hg1-xCdxTe with x = 0.22-0.60 are presented to develop a model for the optical absorption coefficient spectra. The calculated detector spectral response using the new and previously reported absorption coefficient models suggests that next generation IR detectors employing multilayer structures with graded compositional profiles will likely benefit from this new model.
引用
收藏
页码:773 / 778
页数:6
相关论文
共 8 条
[1]   Near-bandgap infrared absorption properties of HgCdTe [J].
Chang, Y ;
Badano, G ;
Zhao, J ;
Zhou, YD ;
Ashokan, R ;
Grein, CH ;
Nathan, V .
JOURNAL OF ELECTRONIC MATERIALS, 2004, 33 (06) :709-713
[2]   THE EXPONENTIAL OPTICAL-ABSORPTION BAND TAIL OF HG1-XCDXTE [J].
FINKMAN, E ;
SCHACHAM, SE .
JOURNAL OF APPLIED PHYSICS, 1984, 56 (10) :2896-2900
[3]   ENERGY-GAP VERSUS ALLOY COMPOSITION AND TEMPERATURE IN HG1-XCDXTE [J].
HANSEN, GL ;
SCHMIT, JL ;
CASSELMAN, TN .
JOURNAL OF APPLIED PHYSICS, 1982, 53 (10) :7099-7101
[4]   MODEL FOR INFRARED-ABSORPTION AND TRANSMISSION OF LIQUID-PHASE EPITAXY HGCDTE [J].
HOUGEN, CA .
JOURNAL OF APPLIED PHYSICS, 1989, 66 (08) :3763-3766
[5]   TRANSPORT STUDIES IN NARROW-GAP SEMICONDUCTORS REVISITED [J].
KRISHNAMURTKY, S ;
SHER, A .
JOURNAL OF ELECTRONIC MATERIALS, 1995, 24 (05) :641-646
[6]   DISPERSION OF THE REFRACTIVE-INDEX OF HG1-XCDXTE [J].
KUCERA, Z .
PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE, 1987, 100 (02) :659-665
[7]   Optical-absorption model for molecular-beam epitaxy HgCdTe and application to infrared detector [J].
Moazzami, K ;
Phillips, J ;
Lee, D ;
Edwall, D ;
Carmody, M ;
Piquette, E ;
Zandian, M ;
Arias, J .
JOURNAL OF ELECTRONIC MATERIALS, 2004, 33 (06) :701-708
[8]   Optical absorption properties of HgCdTe epilayers with uniform composition [J].
Moazzami, K ;
Liao, D ;
Phillips, JD ;
Lee, DL ;
Carmody, M ;
Zandian, M ;
Edwall, DD .
JOURNAL OF ELECTRONIC MATERIALS, 2003, 32 (07) :646-650