Electrical properties of thin films

Abstract

Stoichiometric thin films of were prepared by the thermal evaporation technique; the as-deposited films were non-crystalline and the crystallinity was built in on annealing at 423 K. The crystal structure as determined by both x-ray and electron diffraction showed that tetragonal films of phase were obtained. Both dark electrical resistivity and thermoelectric power (Seebeck coefficient S) were measured for films before and after annealing. The films showed n-type conduction; the existence of two distinct activation energies and belongs to two types of level: a shallow level of before annealing and after annealing and deep levels of for as deposited films and for annealed film. The deep level was also detected by the space charge limited current technique and the trap density is found to be . The obtained results are explained on the basis of an energy diagram of - proposed by Garlick.

A time-resolved microwave conductivity study of the optoelectronic processes in TiO2∣In2S3∣CuInS2 heterojunctions

“…29 For In 2 S 3 , trap levels are reported at 0.29 and 0.35 eV below the conduction band. 24 From the high IPCE values ͓Fig. 2͑b͔͒ for triple layer configurations, one can conclude that under short circuit condition, almost all incident photons yield electrons in the external circuit.…”

“…This value is close to the charge carrier mobilities of n-type In 2 S 3 reported previously. 23,24 Finally, CuInS 2 absorbs all three wavelengths due to its 1.55 eV band gap. Figure 4͑c͒ shows that the charge carrier lifetime of CuInS 2 is much shorter than those of TiO 2 and In 2 S 3 .…”

“…27,28 This is remarkable, since hole transfer between TiO 2 and either In 2 S 3 or CIS is expected to be fast. A plausible explanation is that since TiO 2 and In 2 S 3 are both n-type materials, 24 accumulation layers rather than depletion layers are formed, which creates an energy barrier for hole transfer. The same explanation for TiO 2 ͉ CIS heterojunctions implies that at this interface CIS has turned into n type.…”

Structural and Optical Properties of Indium Sulfide Thin Films Prepared by Silar Technique

“…In 2 S 3 is a wide band gap semiconductor with high photoconductivity and intense luminescence existing in three welldefined crystallographic modifications [1,2]. The room temperature phase, called -In 2 S 3 , is stable up to 420 0 C and crystallizes in defect spinel lattice with high degree of vacancy ordering at tetrahedral cation sites.…”

“…The films can be synthesized using several techniques such as chemical spray pyrolysis (CSP) [14], atomic layer epitaxy (ALE) [15], chemical bath deposition (CBD) [16], chemical vapor deposition (CVD) [11], RF sputtering [17], thermal evaporation [2], organometallic chemical evaporation [18] and Successive Ionic Layer Adsorption and Reaction (SILAR) [19,20]. In the present work, we prepared -In 2 S 3 thin films using SILAR deposition technique, which is a convenient and adaptable method for thin film deposition.…”