Theoretical calculations using a particle flux concept were carried out to determine the optimum substrate temperature for the growth of films of Pb0.82Sn0.18Te alloy on KC1(100) substrates by molecular beam epitaxy. The calculated value of 373 °C was found to be close to the experimentally observed value of 375 °C for Pb0.82Sn0.18Te. During growth a single source at a temperature of 600 °C was used. The grown films were characterized by X-ray diffraction and electrical and optical techniques. © 1988.

T. K.K. Srinivasan

Pukhraj R. Vaya

Jandhyala Sobhanadri

ELECTRIC MEASUREMENTS

Molecular beam epitaxy

Semiconducting Lead Compounds

X-Rays - Diffraction

LEAD TIN TELLURIDE ALLOY

LEAD AND ALLOYS

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Growth of Pb0.82Sn0.18Te by molecular beam epitaxy

Thin Solid Films

The changes in the absorption spectra and the variation of the band edge with temperature have been investigated for an MBE-grown Pb 0.82Sn0.18Te film for temperature-dependent transmittance spectra recorded over the temperature range 90 to 600 K. Analysis of these spectra showed that below 175 K the possible fundamental transition is direct, while at higher temperature it is indirect. Below 425 K dEg1/dT was 4*10-4 eV K-1 with Eg1(0)=0.102 eV for the direct transition. dEg2/dT and Eg2(0) were 3*10-4 eV K-1 and 0.116 eV respectively for the indirect transition. Above 425 K, dEg3/dT and Eg3(0) were 1.1*10-4 eV K-1 and 0.218 eV for the direct transition. dEg4/dT and Eg4(0) were 1.2*10 -4 eV K-1 and 0.192 eV respectively for the indirect transition. These results can be explained well using the proposed band model for this material.

Semiconductor Science and Technology

The temperature-dependent absorption edge of MBE-grown Pb 0.82Sn0.18Te film in the infrared region

Thin epitaxial layers of Pb1−xSnxTe are grown on (100) KCl substrates by molecular beam epitaxy (MBE) using a single Knudsen source. A typical source temperature of 600 °C and substrate temperatures of 250 to 350 °C are used. Laue, X‐ray, RHEED, SEM, and Van der Pauw techniques are employed to characterize these films. Layers 4 to 5 μm thick are grown at a growth rate of 0.75 μm/h. These layers are found to be p‐type having carrier concentrations in the range of 1017 to 1018 cm−3 and mobilities of the order of 103 cm2/Vs at 110 K. The composition x in the films is found to vary with the substrate temperature and the films grown at 325 °C exhibit the same value of x as the source material. Copyright © 1988 WILEY‐VCH Verlag GmbH &amp; Co. KGaA

physica status solidi (a)

Structural and electrical properties of Pb1 − xSnxTe films grown by molecular beam epitaxy

Epitaxial films of Pb//1// minus //xSn//xTe (LTT) were deposited on (100) KCl substrates at 300, 325 and 350C using Molecular Beam Epitaxial (MBE) technique. RHEED, X-ray and Van der Pauw techniques were employed to study surface structure, single crystallinity and electrical properties of these films respectively. The resistivity of these films was found to decrease from 10** minus **2 OMEGA -cm at 300K to 10** minus **3 OMEGA -cm at 100 K. The mobility was found to increase with lowering of temperature in the range 10**2 cm**2/V sec at 300 K and 10**3 cm**2/V sec at 100 K.

Journal	Thin Solid Films
ISSN	00406090
Open Access	No