Effect of boron implantation on the electrical and photoelectrical properties of e-beam deposited Ag–In–Se thin films

Abstract

In this study, e-beam evaporated Ag–In–Se (AIS) thin films were doped by the implantation of boron (B) ions at 75 keV with a dose of 1 × 1015 ions cm−2 and a subsequent annealing process was applied to the doped AIS films at different temperatures under nitrogen atmosphere. The effects of implantation and annealing on the electrical and photoelectrical properties of AIS thin films were investigated through temperature dependent conductivity, spectral photoresponse and photoconductivity measurements under different illumination intensities. The electrical conductivity measurements showed that the room temperature conductivity values were determined as 2.4 × 10−7 (Ω cm)−1, 1.7 × 10−6 (Ω cm)−1 and 8.9 × 10−5 (Ω cm)−1 for B-doped films (B0), B-doped and annealed films at 200 °C (B2) and at 300 °C (B3), respectively. It was observed that the electrical conductivity improved as the annealing temperature increased up to 400 °C at which the AIS thin films showed degenerate semiconductor behaviour. The spectral distribution of the photoresponse curves indicated three local maxima located at 1.63, 1.79 and 2.01 eV for B0 type films, 1.65, 1.87 and 2.07 eV for B2 type films and 1.73, 2.02 and 2.32 eV for B3 type films at room temperature. These three different energy values were ascribed to the splitting of the valence band due to spin–orbit interaction and crystalline lattice field effects. The first energy values of each set were determined to be energy band gaps of the AIS thin films. The photoconductivity measurements as a function of temperature and illumination intensity were performed on the B-doped AIS thin films in order to determine the nature of recombination processes in the films. The photoconductivity values were found to be thermally quenched for all types of thin films and the variation of photocurrent as a function of illumination intensity showed that the dependence of photocurrent on the intensity was supralinear. The two-centre recombination model was applied successfully in order to explain the photoconductivity behaviours of the films.

Influence of Al dopant on structural and optical parameters of AgInSe2 thin film

“…They can also be the type of conductivity as n-type or p-type depending on the type of majority carrier either electron or hole [2]. (AIS) is the best promising absorber materials for photovoltaic cell, because (AIS) have optimum direct energy gap, high optical absorption (_10 −5 cm −1 ) [3]. Melting point and band gap energy of AgInSe2 is better than CuInSe2 for solar cell applications [1] direct gap semiconductors [4] lies between 0.8 and 2.0 eV [5] the crystal structure of AIS is tetragonal structure chalcopyrite with the lattice constant a =b= 6.102 A° and c = 11.69 A° [6].…”

“…The effect of different material doped on AgInSe 2 characterization thin films were investigated by various researches such as the influnce of germanium(Ge) doping on the AgInSe2 thin film properties has been studied good optical transmittance spectra and an increased of n-type conductivity compared with the pure [19]. The effects of boron (B)doping on AgInSe2 by ion implantation and heat-treatment technique with different annealing temperatures 473, 573 and 673K on the electro-optical and electrical properties of thin films, desired behaviours for photoconductive of the B-AgInSe2 thin film when 473K [3].…”

Optical properties of single-crystalline chalcopyrite semiconductor AgInSe2

“…1 Silver indium diselenide ͑AgInSe 2 ͒ is one of the I-III-VI 2 ternary compounds, but its many fundamental properties are not sufficiently evaluated or even unknown. 1,2 The optical properties of AgInSe 2 have been studied using various techniques, such as far-infrared ͑IR͒ reflectivity, 3 optical absorption, 4-14 near-IR-ultraviolet reflectivity, 7,9,15 photoluminescence ͑PL͒, 10,16-21 photoconductivity, [22][23][24][25] spectroscopic ellipsometry ͑SE͒, 26,27 electroreflectance ͑ER͒, 16 thermoreflectance ͑TR͒, 27 and wavelength-derivative reflectivity. 22 Most of these studies were carried out on polycrystalline AgInSe 2 samples.…”

“…22 Most of these studies were carried out on polycrystalline AgInSe 2 samples. 14,15,17,19,20,[24][25][26][27] Kanellis and Kampas 3 grew single-crystalline AgInSe 2 and measured far-IR reflectivity using polarized light. PL measurements on single-crystalline AgInSe 2 samples were performed by several authors; 16,18,21 however, polarization dependence was not taken into consideration.…”

Two impurity energy level regulation leads to enhanced thermoelectric performance of Ag1−xCdxIn5Se8

“…8,16,17 The ternary compound AgIn 5 Se 8 belongs to the A I B 5 III C 8 VItype wide band gap semiconductor family, which is regarded as being composed of an In 2 Se 3 -based (In 2 Se 3 ) 2 (AgInSe 2 ) or (In 2 -Se 3 ) 2.5 (Ag 2 Se) 0.5 pseudo binary alloy. 18 Besides, the structure of these ternary compound is analogous to B 2 III C 3 VItype crystalline structures, 19,20 which allows the incorporated foreign elements to take the most stable valence state, 20 resulting in the reduction in band gap. This is caused by the preference of Ag or Cu incorporation in a-In 2 Se 3 , favoring the formation of Ag 2 Se or Cu 2 Se slab.…”