The growth and the interfacial layer of CdZnTe nano-crystalline films by vacuum evaporation

Study of Te aggregation at the initial growth stage of CdZnTe films deposited by CSS

“…The Te/M ratio evolved with the similar tendency as that of the film deposited by CSS, which was 2.5 [21]. In a CdTe film deposited by MBE on GaAs at the substrate temperature of 563 K, Waag et al [14] found that the Te/M ratio was below 40/60 when the film thickness was less than 10 Å and it approached to 1 as the film being thickened.…”

“…Te aggregation in the beginning is observed in films on different substrates varying from polycrystalline (CdS) to single crystalline (Si and GaAs) [8,14,17,18,21]. Therefore, the influence of the substrate can be ruled out.…”

“…We find that Te aggregation at the initial growth stage is rather common in CdZnTe films deposited from compound sources by physical vapor deposition (PVD), such as MBE, CSS, and vacuum evaporation (VE) [21]. To the best of our knowledge, important questions such as the structure and the evolution of a CdZnTe film with excess Te atoms and the reason why Te aggregates have not been thoroughly addressed yet.…”

Optimization of structural, optical and electrical properties of CdZnTe thin films with the application of thermal treatment

“…The transmittance is also observed to increase continuously and pronounced with the interference fringes at longer wavelength range which revealed the homogenous nature of the films. The optical direct energy band gap and nature of transition are analyzed using Tauc relation [5] and absorption coefficient ( ) was evaluated by standard relation [14]. The linear nature of the Tauc plots (Fig.2b) reveal that the CdZnTe is a direct band gap compound semiconductor material and absorption edge is found to shift towards higher wavelength and red shift is observed with thermal treatment which may be attributed to the improvement in crystallinity as confirmed by typical XRD patterns.…”

“…One of the most important applications of CdZnTe thin film is to use it as the top cell absorber layer in a tandem solar cell when tuned to its higher band gap. The nanocrystalline CdZnTe films may also be used in homojunction solar cells as window layer [4][5]. A number of deposition techniques have been used to fabricate CdZnTe thin films such as vacuum evaporation, chemical vapor deposition, sputtering, close-spaced deposition, molecular beam epitaxy, electrodeposition, pulsed laser deposition, traveling heater method, Bridgman technique etc.…”