Photoelectronic and electrical properties of InS crystals

Abstract

To identify the localized levels in InS single crystals, the dark electrical conductivity, current-voltage characteristics and photoconductivity measurements were carried out in the temperature range of 10-350 K. Temperature dependence of dark electrical conductivity and the space-charge limited current studies indicate the presence of a single discrete trapping level located at (10 ± 2) meV below the conduction band with a density of about 4.8 × 10 11 cm −3 . The conductivity data above 110 K reveal an additional two independent donor levels with activation energies of (50 ± 2) and (164 ± 4) meV indicating the extrinsic nature of conductivity. The spectral distribution of photocurrent in the photon energy range of 0.8-3.1 eV reveals an indirect band gap of (1.91 ± 0.04) eV. The photocurrent-illumination intensity dependence follows the law I ph ∝ F γ , with γ being 1.0 and 0.5 at low and high illumination intensities indicating the domination of monomolecular and bimolecular recombination, respectively. It is observed that the photocurrent increases in the temperature range of 10 K up to T m = 110 K and decreases or remains constant for 110 K < T < 160 K and increases again above 160 K. The temperature dependence of the photocurrent reveals an additional shallow impurity level with activation energies of 3 meV.

Hall effect, space-charge limited current and photoconductivity measurements on TlGaSe2layered crystals

“…In the moderate (210 < T < 170 K) and low (160 < T < 120 K) temperature regions-illustrated in inset-2 and inset-3 of figure 4-the exponential increase in the photocurrent with temperature reveals photocurrent activation energies, E ph2 and E ph3 , of 46 and 26 meV, respectively. Similar behaviour of temperature-dependent photocurrent was also observed for GaSe 0.95 S 0.05 :Na mixed crystals [18], GaSe 0.5 S 0.5 [16] and InS [19] crystals where close photocurrent activation energies were also detected. Finally, the observation of supralinear photocurrent (γ > 1.0) at fixed temperature and thermal quenching of photocurrent at fixed illumination intensity may be attributed to the exchange in the behaviour of the sensitizing centres.…”

Investigation of carrier scattering mechanisms in TlInS2 single crystals by Hall effect measurements

“…The contribution of the energy levels to the conductivities (from deep level to shallower one) was checked by using the modification of Eqn. (1) given elsewhere [15]. The statistical analysis using that method [15] The temperature dependence of carrier concentration is illustrated in Fig.…”

“…(1) given elsewhere [15]. The statistical analysis using that method [15] The temperature dependence of carrier concentration is illustrated in Fig. 2.…”

Physical, optical and nonlinear properties of InS single crystal

“…Gasanly and Aydinli [13] have reported low temperature photoluminescence spectra of InS single crystal excited by the 476.5 nm argon ion laser and have observed three photoluminescence bands centered at 605 nm (A-band), 626 nm (B-band) an 820 nm (C-band). Later, Qasrawi and Gasanly [14] have retrieved information about the localized levels in the forbidden gap of InS crystal from the results of dark electrical conductivity, space-charge limited current and photoconductivity measurements in the temperature range of 10-350 K. Although, few reports on the structural, electrical and optical studies on InS are documented in literature, to our knowledge, there is no report on the nonlinear optical properties of InS single crystals. Z-scan is an established technique to measure the optical nonlinearities in a material [16,17].…”

“…were reported [1][2][3][4][5][6]. However, reports on single crystal InS are scarce [7][8][9][10][11][12][13][14]. partly owing to the difficulty in growing single phase samples.…”