Low-temperature photolLminescence of epitaxial GaSb grown by M O ~P E from TMGa and TMSb on various sdbstrates is studied an0 compared witn exist ng results for GaSb grown oy otner techniques. The enecls of growth condit o n s are cons dereo It is touno that a growtn IemperatJre of 650 .C is too h gh, ana tne layers are of v e r y poor qdality. while below t h e opt mLm temperature of 600 ' C tne growth rate slows. a thoLgh t h e optica quality appears unaftected. lnvestigations into tne range of IIIV ratios over wh ch good qLal ty mater al cou d be grown indicated that I n s factor was more critica for GaSo than for GaAs; So-rich condit.ons proddceo samples w In poor radial ve etlic ency. whale samples grown under Ga-r ch conditions were covered on excess Ga orop ets. n addition. w e found that m common witn otner growth techniqdes, the concentrat on of t h e nat ve aefect n GaSb cou d be controlled dsing the l l l V ratio. and an excel e n t corre ation was found between electrical resu ts and features in tne pnoto um nescence Spectra For layers not lahlce-matcnea 10 t h e substrate. t h e spectrum IS red-sniheo W e surm se tnat th s is d u e to dilferenlia thermal contract on of t h e e p layer and substrate A homoepitaxial sample was chosen for aeta led stday ana lrom the depenaence 01 tho spectra on temperatLre and excitation ntensity. a previoLsiy ooserved bOdnd exciton was confirmed and an acceptor of 15 meV bind,ng energy was founo 107 107b 108 109 219 220 221 222 223 299 302 321 374 395 414 475t 477t 478t 479t 5187 1nAs

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Single and multiple quantum wells of GaSb/GaInSb were grown by metalorganic vapor phase epitaxy. X-ray diffraction on an 80 Å single well confirmed the Ga1−xInxSb composition to be x=0.15, for which the lattice mismatch is ≊1.0%. Photoluminescence and photoconductivity from this sample both showed a signal due to carriers in the well, the position of which was in good agreement with the calculated band diagram. Shubnikov–de Haas oscillations in the transverse magnetoresistance (ρxx) of a four-period multiquantum well, and the associated quantum Hall effect, indicated that a two-dimensional hole gas was present in one of the wells. Unusually, the strongest oscillations were seen for occupancy of an odd number of (spin split) Landau levels (ν=1,3,5,...,etc.) This sample also showed luminescence peaks at 738 and 755 meV which were attributed to recombination in the wells.

Magnetctranspon and Optical measurements have been carried out on (OOl] and piezoelectrically active [l 111 InGaSb/GaSb and InAslGaSb structJres. In accordance with theory, these comparative swd'es reveal enhanced carrier density and mobility for growth in the (1 11) oireaion. The Observed Stark sh:hs, of up to 100 meV, in the (111) oriented InGaSb/GaSb structures are well accounted for by the estimated bL:it-:n piezoelectric field, of the order d 1 x lo5 V an-'. The acsorpticn coefcient of [ill] or;ented InAs/GaSb superlahices shows s:gn:ficant ennancement. cm-2)938 SLS 15 40 50 1.3 380 5.0 33000 5.9 9300 932 SLS 15 40 100 high resistance 27 22500 6.0 1200 930 SLS 15 80 100 2.1 730 4.8 24400 12.0 450 G G 431 a s i 5 80 5% 8.7 4.3 2 E 0 I u.u 945 DQW 15 40 30 2.1 9200 2.4 18200 6.1 6600 946 DQW 15 40

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