Optical and Magnetooptical Studies of the Interband Transition of Holes in Tellurium

Abstract

The interband transitions of holes in tellurium by absorption experiments are investigated in the energy range 100 to 170 meV on variously doped single crystals (lo1* to 5 x 1017 holes/cm3) between 1.6 and 77 "K. Calculations of the absorption spectrum due to the direct inter-valence band transitions are performed, using for the two split valence bands the dispersion relation e ( K ) = -a ki -b k l 5 VJ.2 + 2 a J. to k:. Theoretical

Valence and Conduction Band Structure and Infrared Optical Properties of Tellurium in the Presence of Pressure

“…It can be attributed to the direct allowed interband transition between the P,valence band state and the P4, 6-conduction band states. At low temperatures in the neighbourhood of H the 11 pm-band shows a threefold substructure which strongly depends on temperature and hole concentration [14]. In [14] the first peak (R) of the 11 pm-band a t 126 meV is attributed to the intervalence band transition H, --f H,, while the third peak (y) a t 150 meV is ascribed to the intervalence band transition P, --f P, into the camel backs of the uppermost valence band.2) The interpretation of the latter peak is argued against in [16].…”

“…In [14] the first peak (R) of the 11 pm-band a t 126 meV is attributed to the intervalence band transition H, --f H,, while the third peak (y) a t 150 meV is ascribed to the intervalence band transition P, --f P, into the camel backs of the uppermost valence band.2) The interpretation of the latter peak is argued against in [16]. The second peak of the 11 pm-band a t 128meV is due to a transition between band and acceptor states [14]. The selection rules for the direct optical band-band transitions a t H and P are shown in Fig.…”

“…The electron states at H' and P' are degenerated with those at H and P, respectively, because of time reversal symmetry. The infrared absorption spectrum of tellurium shows an absorption band above 0.13 eV for the light polarization parallel t80 the c-axis (11 pmband) [14] and a considerable increase of the absorption above 0.33 eV for the light polarization perpendicular to the c-axis [MI. The latter structure (E,) represents the fundamental absorption edge [15].…”

Theory of the photon‐drag effect in semiconductors with elliptical isoenergetic surfaces and its application to tellurium crystals

“…[8,12]), the gap AE is greater than it follows from (12). At low temperatures AE > 117 meV, that means A o -AE < 0 for CO, laser photons.…”

Longitudinal Photon Drag in p‐Type Tellurium

“…All photoeffects of free carriers are favoured by a high absorption cross-section of the carriers. The absorption cross-section 8, of holes in tellurium for CO, laser radiation (A = 10.6 pm) is the highest of any semiconductor known, since (i) the quantum energy agrees very well with the distance of sub-valence bands H, and H, (hv = 117 nieV; 8E = 122 meV a t 77 K ) [7];…”