Tin-related double acceptors in gallium selenide single crystals

Abstract

Gallium selenide single crystals doped with different amounts of tin are studied through resistivity and Hall effect measurements in the temperature range from 30 to 700 K. At low doping concentration tin is shown to behave as a double acceptor impurity in gallium selenide with ionization energies of 155 and 310 meV. At higher doping concentration tin also introduces deep donor levels, but the material remains p-type in the whole studied range of tin doping concentrations. The deep character of donors in gallium selenide is discussed by comparison of its conduction band structure to that of indium selenide under pressure. The double acceptor center is proposed to be a tin atom in interlayer position, with a local configuration that is similar to that of tin diselenide. The hole mobility exhibits an anomalous dependence on the tin content, attaining its maximum value in the ingot with 0.2% nominal tin content. This is proposed to be related to impurity pairing effects giving rise to thermal shallow acceptors with low ionization energy and low carrier scattering cross section, making the hole mobility to be controlled by phonon scattering mechanisms even for relatively high impurity content.

Acceptor levels in GaSe:In crystals investigated by deep-level transient spectroscopy and photoluminescence

“…Acceptor levels in undoped p-GaSe ͑Ref. 9͒ and GaSe doped with elements, such as Sn, 8 Cd, 10 Mn, 11,12 Cu, 13,14 Er, 15 N, 16 and Co, 17 have been investigated. However, to our knowledge, the acceptors levels of GaSe:In have not been yet reported.…”

“…The value is high enough to make GaSe:In potential candidates for room temperature radiation detectors although the dependences of hole mobility on temperature and indium concentration need further investigation to clarify the mechanism of hole scattering by the dopants and phonons. 8 The carrier mobility-lifetime product is an important figure of merit in the evaluation of x-ray and gamma-ray semiconductor detectors; the carrier lifetime is determined by the trap concentrations and the capture cross sections.…”

Transport measurements under pressure in III–IV layered semiconductors

“…The present studies were performed in InSe and GaSe monocrystals grown by the Bridgmann method [29,30]. The samples used for the measurements were typically 30-40 µm thick and 3 × 3 mm 2 in size.…”

Structural, electrical and optical properties of Ge implanted GaSe single crystals grown by Bridgman technique

“…There are markedly many studies carried out to observe the influence of chemical doping in GaSe crystals with different elements, such as Cl [11], Sn [12][13], Cu [14], Li [15], Ag [16], and Zn [17]. Although chemical doping is the most commonly used method, it has some drawbacks since the dopant is added before the growth process.…”