Abstract
The objective of this research project was to analyze the photo-degradation of the photocurrent of the electron beam evaporated amorphous semiconducting Se90-xSb10Inx (0 ≤ x ≤ 15) thin films (α-Se90-xSb10Inx). The photo-induced effects in amorphous semiconducting Se90-xS10Inx (0 ≤ x ≤ 15) thin films were studied using two approaches: steady state and transient photoconductivity. The degradation of photocurrent has been explained on the basis of theoretical models. The steady state analysis has been performed by plotting the photocurrent (Iph) versus light intensity (F) and this variation follows a power law Iph=Fy. The value of exponent γ lies between 0.5 and 1.0, which indicates there exists a continuous distribution of localized states in the mobility gap of Se90-xSb10Inx (0 ≤ x ≤ 15) thin films. For transient photoconductivity, when the samples were illuminated with light, the photocurrent quickly reaches the maximum value and thereafter, it starts decreasing with the exposure period and becomes stable after approximately 15 minutes of exposure. This kind of phenomenon is termed as photodegradation of photocurrent. The results have been explained on the basis of charged defect model and the inter-cluster interaction model. High photocurrents are found for α-Se75Sb10In15 system, which is even higher than the parent system Se₉₀Sb₁₀. The influence of bias voltage on the dark current and photocurrent of the Se90-xSb10Inx (0 ≤ x ≤ 15) thin films is also investigated. Both the dark and photocurrent increase with increase in the bias voltage. The compositional dependence of dark conductivity, photoconductivity and the photosensitivity shows a minimum at 5 atomic percentage of Indium (In) concentration, which has been explained based on chemically ordered network model and the topological model.
Highlights
Introduction and MotivationAn introduction to amorphous semiconductors, their classifications and technological applications are briefly summed up in this chapter
There is a minimum in the photocurrent observed at the 5 atomic percentage of indium concentration which is consistent with the minimum observed in the DC activation energy and the optical band gap of Se9o-xSb 10Inx (0 ~ x ~ 15) thin films [43]
Bulk samples of Se9o-xSb101nx (0 :$; x::; 15) system were prepared by conventional melt quenching technique and the thin films were prepared by electron beam evaporation
Summary
An introduction to amorphous semiconductors, their classifications and technological applications are briefly summed up in this chapter. Amorphous materials are not new from structure point of view. The structure of amorphous solid is characterized as an irregular arrangement of atoms in contrast with crystalline solids whose structure has a periodic array of atoms [2]. The periodicity of the structure is interrupted at the so-called grain boundaries. Among them chalcogenide semiconductors are one of these families due to their interesting properties. Amorphous semiconductors from Selenium based systems have attracted attention of many researchers. Several studies on thermal and structural properties have been performed on the amorphous selenium obtained by vapor deposition, quenching and ball milling [12-20]. Se-Sb based alloy films are thought to be one of the most promising media, which make use of phase change between an amorphous state and crystalline state. The dielectric studies on Se-Sb based alloys have been recently reported [4]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
