The effect of the electron irradiation on the electrical properties of thin polycrystalline CdS layers

Abstract

The electrical properties of nonirradiated and electron irradiated structures, containing a polycrystalline thin layer of CdS, sandwiched between two gold electrodes, were investigated. The thin films of CdS, obtained through thermal-vacuum evaporation on the glass substrate at a temperature of 220 °C, were subjected to two sessions of irradiation with 7 MeV electrons to the fluences of 4×1015 and 6×1015 e/cm2, respectively. In the case of nonirradiated structures, under low voltages, the Ohm’s law is followed with a thermally activated electron concentration of n0≅3×1016 cm−3, an electron mobility μ0≅0.1 cm2/V s and a room temperature electrical conductivity σ0≅4×10−4 Ω−1 cm−1. In this range of voltage the electron irradiation induces a small increase in the activation energy of mobility, determining, of course, a small decreasing of the mobility. At high-applied voltage, there is a space-charge-limited conductivity controlled by a single trap level having the depth of Ec−Et≅0.086 eV and the total trap concentration Nt≅8.9×1015 cm−3. In this range of voltage, the electron irradiation modifies the trap distribution. After the first session of irradiation a uniform trap distribution appears and after the second session, an exponential trap distribution was induced in the band gap of CdS layer. All the induced trap distributions are characterized and their effect on the charge transport mechanisms is discussed.

Synthesis and structural, optical and thermal properties of CdS:Zn2+ nanoparticles

“…CdS is an important semiconductor compound of the II-VI group with excellent physical properties and band gap energy of 2.42 eV. It has been extensively studied due to its potential application in field effect transistor, lightemitting diodes, photocatalysis, biological sensors, solar cells and photodegradation of water pollutants (Alivisatos 1996;Colvin et al 1994;Klein et al 1997;Ruxandra and Antohe 1998;Romeo et al 2010;Beecroft and Ober 1997). The electronic properties of CdS nanoparticles doped with transition metals are strongly influenced by the doped transition metals (Liu Kewei et al 2007).…”

Effect of plasticizer on safranine-T-dye-based solid-state photo electrochemical cell

“…The dark current-voltage nature for organic PV cells, particularly made from organic semiconducting dyes and pigments have been extensively studied [14][15][16][17]. In our earlier work [8], we have shown that dark current-voltage curve for safranine-T-dye-based PEC can be explained using the model used for OLED.…”

Spectroscopic Characterization of 400℃ Annealed Zn_xCd_1-xS Thin Films

“…이들은 우수한 광전 특성을 보여주기 때문 에 박막화할 경우, 이종접합형 광기전(photovoltaic)의 태 양전지나 광전도 소자(photoconductive device)로서 응용가 능성이 높다. 한편, 에피박막으로 제작한 양자우물(quantum well) 등에서 나타나는 여기자 국재화(exciton localization) 관점에서 보면, Zn x Cd 1-x S 박막은 높은 냉광(luminescience) 효율을 실현하는데 아주 유망하므로, 최근 광 범위하게 연구되고 있다 [3], [4] . ZnxCd1-xS 박막은 Cd 함유량을 제어함으로써 넓은 응용 범위를 망라할 수 있다.…”