The growth of p-type TlGaSe2((1-x))S-2x single crystals

TIGaSe2(1-x)S2x single crystals were grown by the modified Bridgman-Stockbarger method in our crystal growth laboratory. A(III)B(III)C(2)(VI), compounds are formed of elements from vertical groups of the periodic table (group III: Tl, Ga, In, group VI: Se, S, Te) and are classified into two types. The first type has a layer structure: TlGaSe2, TlGaS2 and TlInS2. The second type has a chained structure: TlInSe2, TlInTe2 and TlGaTe2. None of the grown crystals had cracks and voids on the surface. The freshly cleaved crystals had a mirror-like surface and there was no need for mechanical or chemical polishing treatments. By the hot probe technique, we have found that the crystals were of p-type. The ingots produced were single crystalline and the useful region of single crystal was 90% of the bulk approximately. The absorption measurements were performed with steps of 10 K if changes were small, and with steps of 3 and 5 K if changes were large in the direct and indirect band gaps energies. The direct and indirect band gaps for TlGaSe2(1-x)S2x samples were calculated as a function of temperature.