Multiple quantum well InAs/GaSb laser heterostructures with type III (type II broken gap) band alignment in the active region have been grown by molecular beam epitaxy. Intense electroluminescence was observed at room temperature (RT) with peak emission wavelengths in the range 1.95–3.4 μm. RT lasing has been achieved at 1.98 and 2.32 μm for the structures with 6 and 12 Å thick InAs quantum wells, respectively.

Thin films of Cu2ZnSnS4 (CZTS) were deposited on Pyrex substrates at various temperatures by spray pyrolysis technique from aqueous solution containing an economic stannous chloride (SnCl2) precursor for the tin and the effect of substrate temperature on the structural and opto-electronic properties was investigated. X-ray diffraction patterns and Raman spectroscopy reveal that all the CZTS films exhibited kesterite structure with preferential orientation along the (1 1 2) direction and some secondary phases. Also, they possessed different band gaps, which were found to lie between 1.52 and 1.81 eV, indicating that CZTS compound has absorbing properties favorable for applications in solar cell devices. Van der Pauw technique and Hall effect measurements were used to determine the electrical properties of CZTS films and the resistivity was of about 0.12 Ω cm for film grown at 280 °C.

No abstract

The molecular beam epitaxy growth of strained (Ga, In)Sb/GaSb quantum wells is investigated. In a narrow range of growth conditions, (Ga, In)Sb quantum well structures exhibiting excellent structural properties as well as intense and narrow photoluminescence transitions are obtained. Stimulated emission at 1.98 µm is observed at room temperature from laser diodes with Ga 0.74 In 0.26 Sb/GaSb strained quantum wells as the active zone. The lasers exhibit threshold current densities as low as 280 A cm −2 and a characteristic temperature of 75 K.