Wyniki wyszukiwania - BazTech

1

Stimulated and spontaneous far infra-red emission from uniaxially strained gapless Hg₁₋xCdxTe

Gasan-Zade S. G., Strikha M. V., Shepelskii G. A.

Opto-Electronics Review

|

2010

|

Vol. 18, No. 3

305-309

EN

The intensive far infra-red irradiation in the range of 80–100 μm was observed in uniaxially strained gapless p-Hg₁₋xCdxTe (MCT) with x = 0.14 in the strong electric field. The inverse occupation in strained MCT is created because the hot electrons distribution occurs in the c-band under impact ionization, while the holes are localized near the v-band top. The probability of band-to-band radiative transition increases dramatically when the acceptor level becomes resonance in the v-band. At threshold values of strain and electric field (P = 2.5-2.7 kbar, E = 50-55 V/cm), increase in irradiation (by 3 orders of magnitude) and increase in current (by 4-6 times) occur.

2

Insight into precursor kinetics using an infrared gas analyser

Kłos K., Piotrowski A., Gawron W., Piotrowski J.

Opto-Electronics Review

|

2010

|

Vol. 18, No. 1

95-101

EN

Precursor kinetics and its influence on MOCVD growth was investigated using an infrared absorption gas analyser. After several refinements, the analyser was able to be used to measure time dependent concentrations of precursors in the growth zone. Changes were induced by periodic switching of corresponding bubbler valves. It was proved that precursor transport could be accurately described by the combined plug flow and perfectly mixed tank model. The studies of the precursor trans-port are strategically important for the growth of multilayer structures, when growth time of particular layers becomes comparable to delays and time constants. One example is quantum wells or interdiffused multilayer process (IMP) used in the growth of Hg1-xCdxTe heterostructures, where knowledge of precursor transport characteristics is vital for understanding and properly designing that growth. The model parameters, sc. the delays and time constants for DIPTe and DMCd, were evaluated for various growth conditions and then successfully used to optimise the growth of complex Hg1-xCdxTe heterostructures.

3

Badania wzrostu HgCdTe metodą MOCVD w laboratorium VIGO/WAT

Gawron W., Grudzień M., Kłos K., Piotrowski J.

Elektronika : konstrukcje, technologie, zastosowania

|

2006

|

Vol. 47, nr 3

14-19

PL

Od 2003 r. w laboratorium VIGO/WAT prowadzono badania nad wzrostem heterostruktur Hg1-xCdxTe o niemal dowolnych profilach składu i poziomie domieszkowania, niezbędnych dla zaawansowanych przyrządów fotoelektrycznych. MOCVD w zastosowaniu do Hg1-xCdxTe jest jedną znajtrudniejszych technologii epitaksjalnych. Omówiono zagadnienia związane ze wzrostem i charakteryzacją warstw Hg1-xCdxTe w technologii MOCVD. Dokonano pomiarów insitu względnego stężenia związków metaloorganicznych analizatorem gazu własnej konstrukcji. Podsumowano stan domieszkowania warstw Hg1-xCdxTe z uwzględnieniem ostatnich badań. Opracowana technologia MOCVD została zastosowana do otrzymywania wszystkich typów produkowanych w VIGO System detektorów podczerwieni pracujących w temperaturach pokojowych.

EN

Since 2003 VIGO System S.A. together with MUT (Military University of Technology) are doing joint efforts to improve MOCVD growth of Hg1-xCdxTe. Photodetectors optimized for any wavelength within 1-15 um spectral range requires complex heterostructures with multiple layers with homogeneous composition and doping, characterized by steep interfaces. Hg1-xCdxTe growth with interdiffused multilayer process (IMP) technique has been improved using self-made in-situ monitoring of gas delivery to the growth zone. The other issues addressed in this work were growth of heavy As-doped low-x and heavy l-doped high-x materials. Special modification to IMP process has been applied for in-situ control of stoichiometry. To maintain low vacancy concentration, special growth finish procedure has been developed. No post-growth thermal anneal was necessary for device-quality material. The MOCVD grown heterostructures have been successfully used for advanced uncooled infrared photodetectors such as multiple heterojunction photodiodes, multicolor and multiabsorber devices with specially shaped spectral response.