Influence of impurities and free carriers on the optical properties of CuInSe2

Abstract

As‐grown n‐type CuInSe2 single crystals are investigated by electrical, optical transmittance and reflectance, and photoconductivity measurements. It is established that two donor states with ionization energies of (7 ± 1) meV and (225 ± 5) meV and one deep acceptor state with an ionization energy of about 400 meV are simultaneously present in the crystals. The observed absorption due to free electrons can be understood in terms of the scattering mechanisms known to be important in n‐type CuInSe2. The temperature coefficient of the gap energy is found to be dEg/dT = − (1.6 ± 0.3) × 10−4 eV/K from photovoltage measurements.

Deep level transient spectroscopy study of electron-irradiated CuInSe2 thin films

“…[7][8][9][10][11][12] These reported values are close to the present results found in A-type samples. [7][8][9][10][11][12] These reported values are close to the present results found in A-type samples.…”

“…On the other hand, the deep level with activation energy of about 220 meV was not reported by means of the DLTS study, but it was reported in the light absorption 11 and Hall-effect measurements. 12 The reported activation energies are close to the estimated value of the electron-irradiated sample in this study.…”

Ionicity of the chemical bond in AIBIIIC semiconductors

“…I n recent years measured values for the electronic dielectric constant E of most of the copper compounds and also a few of the silver compounds have been reported (HORIG et al 1980;RIEDE et al 1978RIEDE et al , 1980SOBOTTA et al;WEMPLE et al). We will consider Figure 2 for CuInSe,.…”

Pulsed Electrochemical Deposition of CuInSe2 and Cu(In,Ga)Se2 Semiconductor Thin Films

“…Absorber layer is the key element of solar cells, which is produced mainly from the p-type semiconductor in thin films solar cells. The electrical properties of Cu ternary semiconductors are determined by native defects [4]. There are three possible electrically actives defects namely, vacancies, interstitials and antisite defects [5][6][7].…”

“…Samples with p-type conductivity are grown if the material is Cu-poor and is annealed under high Se vapor pressure, whereas Cu-rich material with Se deficiency tends to be n-type. CIS films when suitably manufactured tend to be p-type because of the low energy of formation of copper vacancies which give the material its conductivity [4,7,9]. CIS solar cells yielded relatively lower open circuit potentials due to its small bandgap.…”