Growth and optical parameters of GaSe:Te crystals

Abstract

A series of technological experiments on the growth of GaSe:Te single crystals by the Bridgman-Stockbarger method is performed. Surface micromorphology and mechanical properties of crystals with different doping levels are studied. Spectral dependences of the complex refractive index are obtained using ellipsometry. The experimental data are approximated within the Lorentz-Drude model.

Defects in GaSe grown by Bridgman method

“…Due to interesting semiconductor properties, GaSe is used in microelectronic and epitaxial technologies (Emery et al, 1992;Rudolph et al, 2005;Ho et al, 2006;Huang et al, 2010;Late et al, 2012). The pronounced layered crystal structure of GaSe, space group P6m2, where dense atomic layers are linked by relatively weak van der Waals forces, defines many specific physical and chemical properties of GaSe, such as high anisotropy of mechanical, thermal, linear and nonlinear optical parameters, higher dop- (Cenzual et al, 1991;Fernelius, 1994;Singh et al, 1998;Abdullaev et al, 2002;Andreev et al, 2006;Feng et al, 2008;Abdinov et al, 2010;Sarkisov et al, 2010;Zhang et al, 2011;Isik & Gasanly, 2012;Atuchin et al, 2013a,b ;Kato et al, 2013). The weak interlayer chemical bonds in the GaSe structure results in low mechanical properties and high GaSe crystal cleavage.…”

“…The weak interlayer chemical bonds in the GaSe structure results in low mechanical properties and high GaSe crystal cleavage. This provides a possibility to prepare the large area (001) crystal surface by a simple cleavage technique, and the cleaved surface commonly possesses optical quality and atomic level flatness (Fernelius, 1994;Sarkisov et al, 2010;Borisenko et al, 2011;Isik & Gasanly, 2012;Atuchin et al, 2013a,b;Guo et al, 2013b;Ni et al, 2013). It should be pointed that the cleaved GaSe(001) surface shows specifically high chemical inertness in the air under normal conditions similar to several other layered chalcogenides (Tambo & Tatsuyama, 1985;Atuchin et al, 2011;Yashina et al, 2013).…”

“…Thus, this study is aimed at the growth of a low-defect GaSe single crystal by the developed Bridgman technique and evaluation of defect structure of the crystals. The point defects will receive proper attention because doped GaSe commonly possesses increased hardness, and the creation of interlayer links by admixture atoms and defects may be supposed (Fernelius, 1994;Mosca et al, 2002;Andreev et al, 2006;Feng et al, 2008; Rak et al, 2010;Sarkisov et al, 2010;Atuchin et al, 2013a;Guo et al, 2013a).…”

Effect of adding Te to layered GaSe crystals to increase the van der Waals bonding force

“…[5][6][7][8][9] Widefrequency-tunable terahertz (THz) waves can be generated from GaSe crystal based on the non-linear optical (NLO) process such as difference frequency generation (DFG). [5][6][7] GaSe crystal has a high second-order NLO coefficient (d 22 ¼ 54 pm/V). This means GaSe THz emitter based on DFG is expected to be a highly efficient THz source.…”

“…Therefore, quantitative and direct measurements of the bonding energy are required in order to obtain a crucial understanding of 2D semiconductor materials. Until now, the GaSe 1-x Te x crystals have been investigated for modification of GaSe optical properties [18][19][20][21][22] and frequency conversion efficiency. [23][24][25][26][27]…”