Weak-Field Magnetoresistance inn-Type Aluminum Antimonide

Abstract

Galvanomagnetic measurements have been carried out on a number of single-crystal samples of w-AlSb(Te), with room-temperature carrier concentrations between 5X10 16 cm -3 and 2.5XlO 17 cm" 3 . The measurements were carried out over the temperature range 77 to 500°K. An impurity activation energy, extrapolated to 0°K, of 0.068 eV is obtained from the Hall data. Above 250°K, the temperature dependence of the Hall mobility is proportional to J 1-1 -8 . Magnetoresistance measurements were performed at fixed temperatures in the range 77 to 295 °K. The magnetoresistance was found to be proportional to H 2 up to at least 30 kG. The relations between the various magnetoresistance coefficients follow very closely those required for a [100] multivalley conduction band. The anisotropy parameter K -(mu/mi)(ri/ri\) is found to be ^7 at room temperature in the sample of lowest carrier concentration (where the m's are the effective masses and the r's the relaxation times referred to directions parallel and perpendicular to the unique axis of a spheroidal surface of constant energy). This value decreases to ^3 at 77°K, suggesting increasing anisotropy of scattering due to ionized impurities. An argument is presented in favor of the prolateness of the ellipsoids. Assuming TU/TI=1, K-7, six valleys, and a conductivity effective mass of O.SOmo (where mo is the freeelectron mass), we obtain wn = 1.50mo, mi-0.21mo, and a density-of-states mass mz>* = 1.34mo.

Piezoresistance and Piezo-Hall Effects inn- andp-Type Aluminum Antimonide

“…21 A possible ambiguity in the nature of the valence band deduced from piezoresistance results only or magnetoresistance results only 22 is removed by comparing our results with magnetoresistance results on ^?-AlSb by Stirn and Becker. 23 Results of our measurements of the piezo-Hall effect…”

“…32 The actual dependence of K on temperature for w-AlSb was found recently from magnetoresistance measurements by Stirn and Becker. 21 By combining their values of K [see Fig. 5 (b)] with our values of in, we have obtained the values of S u at various temperatures which are shown in Fig.…”

Spectroscopy of the solid-state analogues of the hydrogen atom: donors and acceptors in semiconductors

“…Onton (1971) has reported transitions from the ground states of Si, Te and S donors associated with the lower X conduction band to excited donor states associated with the next-higher lying X band as well as the photoionisation into it. He was able to experimentally deduce the X3-xl interband energy to be (355 +_ 3) meV with the conductivity effective mass of the higher band of (0.14 k 0.02) m. Ahlburn and Ramdas (1968) have studied the photoexcitation spectra of tellurium and selenium donors in aluminium antimonide which has a multi-valley conduction band with minima along (100) (Ghanekar and Sladek 1966, Stirn and Becker 1966, Laude et a1 1970. The observed lines have been ascribed to ls(A1) -+ np transitions.…”

Extrinsic point defects in aluminum antimonide

“…While all interstitial configurations considered are local minima, they are always much higher in energy than the respective X Sb defect. Although there is supporting experimental evidence of the existence of shallow donor levels, 26,27 it is firmly established that the ground-state of these donors for electron chemical potentials near the conduction band minimum is actually a DX-center 28,29 associated with a deep level. [30][31][32] As indicated in Sec.…”