Hopping conductivity in p-CuGaSe2 films

Abstract

The results of resistivity measurements on p-type CuGaSe2 films are presented and analyzed within the framework of different hopping conductivity models. Both the Mott [N. Mott and E. A. Davies, Electron Processes in Non-Crystalline Materials (Clarendon, Oxford, 1979); N. F. Mott, Metal-Insulator Transitions (Taylor & Francis, London, 1990)] and the Shklovski-Efros [Electronic Properties of Doped Semiconductors (Springer, Berlin, 1984)] regimes of variable-range hopping are observed. The values of the characteristic and transition temperatures as well as the complete set of parameters describing the properties of the localized holes (the localization radius, the dielectric permeability, the width of the Coulomb gap, and the values of density of states at the Fermi level) are determined.

Exciton spectra and energy band structure of CuGaSe2single crystals

“…Devices based on CuGa 1−x In x Se 2 have demonstrated efficiencies up to 19.3% [3]. Some optical and transport measurements were carried out on CuGaSe 2 thin films and single crystals [4][5][6][7][8][9][10][11][12][13] and values of the fundamental gap and its temperature dependence, the crystal field and spin-orbit valence band splitting as well as phonon and exciton parameters and possible defect level schema were reported. The energy band structure of I-III-VI compounds has been calculated as the nearest zincblende analogue [14].…”

Negative Magnetoresistance in Hopping Regime of Lightly Doped Thermoelectric SnSe

“…Variable range hopping is a widely used concept to explain low-temperature electrical resistivity in doped semiconductors [ 37 , 38 , 39 , 40 , 41 ], although its applicability may sometimes be limited to a relatively narrow temperature range [ 42 , 43 , 44 , 45 , 46 ]. It is well-established that in the case of variable range hopping, the electrical resistivity follows a particular behavior described by the equation: where is a temperature-independent prefactor, and is for Mott variable range hopping (VRH) in the 3D case and for Shklovskii–Efros (SE) type hopping.…”

Birefringence of CuGaxAl1 −xSe2crystals

“…The symmetry of the upper valence band and the lower conduction band is V 7 and C 6 , respectively. The excitonic states are formed when the condition hω = E C − E V is fulfilled [16][17][18][19].…”

“…These compounds possess a strong anisotropy of optical properties both in the visible and infrared spectral range. Some optical and transport measurements were carried out on CuGaSe 2 thin films and single crystals [7][8][9][10][11][12][13][14][15][16][17][18], and values of the fundamental gap and its temperature dependence, the crystal field and spin-orbit valence band splitting, as well as phonon and exciton parameters and the defect level schema were reported. The energy band structure of I-III-VI compounds has been calculated as the nearest zinc blende analogue [19,20].…”