Toward CdCl2 activation on CdSe thin films for absorber layer applications

Photosensitivity and Physical Properties of ITO/CdSe/Ag Thin Films Growth by CBD Technique

“…The CdSe film has a direct transmission r=1/2. The figure (1) shows that the Eg value of model (A) and the deposited on the glass substratesis (2.14 eV), the E g of model (B) deposited on ITO substrateis (2.1 eV), and the E g of model (C), which is also deposited on ITOis (1.9 eV), 1) and nearly agree with [2] and [19],this thickness variation is due to the different stacking and growth of grains on top of each other during the thin film formation process [20].All these band gaps are higher than the value of Eg in bulk CdSe (1.7 eV) due to the quantum confinement effect [18].…”

“…The plot of (αh𝜈) 2 vs. h𝜈 for CdSe films as shown in Fig. (1).which shows the relationship between the square of the absorption coefficient and the energy of a photon, based on the Tauc's relationship [18]: αh𝜈 = A (h𝜈 -E g ) r …………………………….. (2) Where A is a constant, Eg is the material's optical band gap, and the exponent r depends on the kind of transition. The r can have values of 1/2, 2, 3/2, and 3 corresponding to allow direct, allowed indirect, forbidden direct, and forbidden indirect transitions, respectively.…”

“…The dark and light I-V characteristics curve of deposited CdSe films with different film thickness values and under different illumination intensities are shown in Fig. (2). Where CdSe was deposited on glass and ITO substrates, where ITO substrates are considered as a transparent conductive electrode and silver paste was chosen as another conductive electrode to ensure the good electrical conductivity of the films.The relationship in Fig.…”

“…Finally the illumination intensity with Photosensitivity for different thicknesswere listed in table (2).…”

“…Among the most significant semiconductors are the compounds of the periodic table group (II-VI), including the compounds that contain cadmium (Cd), such as (CdSe, CdS, CdTe) and others, which are characterized by having a wide and direct energy gap [1].Cadmium selenide (CdSe) is one of the most important semiconductor compounds that fall in to the Group II-VI of the periodic table, and it is widely used in optoelectronics due to its direct bandgap energy (1.74 eV) and optical absorption coefficient in the visible region of the solar spectrum. It is of the negative type (n-type), and it can be converted to the positive type (p-type) through doping [2] and [3].The CdSe film can be used in many applications, including solar cells [4], photodetectors [5], photosensors or photovoltaic solar cells [6], and thin-film diodes [7] or for a pn-junction [8], and it can be prepared using a variety of deposition methods, such as thermal evaporation [9], Successive Ion Layer Adsorption and Reaction Method (SILAR) [10], spray pyrolysis technique [11], Solvo thermal technique [12], Sol-gel technique [13], chemical bath deposition method [14].This is the method employed in this study to prepare the films. It is a simple and low-cost technique for creating films, and it is characterized by the preparation of thin films with large areas and nano forms, and the deposition temperature is low.…”