Use of CdS:O and CdSe as Window layers for CdTe Photovoltaics

Microscopic Analysis of Interdiffusion and Void Formation in CdTe(1–x)Sexand CdTe Layers

“…Extracted line-scan data shows an overlap of S and Se signals ( Figure 4 f), confirming the formation of the CdS (1– x ) Se x phase at the interface between the two layers, which was postulated as the reason for the enhanced losses at a short wavelength in previous work. 10 , 13 , 30 The Te EDS map ( Figure 4 e) shows the negligible Te content in the CdS/CdSe layer region and only the minimal Se content in the CdTe layer at the near interface. We also note that the Te signal is heavily influenced by overlap with the Sn signal coming from beam spreading into the FTO; hence, the increase at the near interface is likely artifact.…”

“… 4 , 5 This led to higher band gap alternatives to CdS being investigated with mixed success. 6 − 10 The use of CdSe then emerged as an alternative approach to CdS removal. As CdSe has a band gap of 1.7 eV compared with 2.5 eV for CdS, this approach seems counterintuitive as one would anticipate enhanced optical losses by incorporating this layer into the device structure.…”

“…Previously, CdS was ubiquitous as the defined n-type partner layer for CdTe PV. However, due to parasitic absorption at short wavelengths (<550 nm), the device short-circuit current density ( J SC ) was always compromised. , This led to higher band gap alternatives to CdS being investigated with mixed success. − The use of CdSe then emerged as an alternative approach to CdS removal. As CdSe has a band gap of 1.7 eV compared with 2.5 eV for CdS, this approach seems counterintuitive as one would anticipate enhanced optical losses by incorporating this layer into the device structure.…”

20%-efficient polycrystalline Cd(Se,Te) thin-film solar cells with compositional gradient near the front junction

“…However, previous works have shown that this strategy does not work, because simply depositing these layers only leads to the formation of an individual wurtzite Cd(S,Se) layer (Supplementary Fig. 1b) with a hetero interface between with the Cd(Se,Te), as demonstrated by several groups 6,34,[38][39][40] . Firstprinciples calculations have shown that the mixing enthalpies of CdS 0.5 Se 0.5 , CdSe 0.5 Te 0.5 , CdS 0.5 Te 0.5 are 3, 8, 25 meV, respectively, suggesting the high propensity to form Cd(S,Se) 4 .…”

Electrical and Optical Properties of Boron Doped Zinc Oxide Thin-film Deposited by Metal-organic Chemical Vapour Deposition for Photovoltaic Application

“…Also, the ZnO has a wide range of applications in electronic circuits such as radiation detectors and solar cells hence, researchers have focused on the improvement of its electrical properties [8], optical properties of undoped [9] and doped [10] ZnO films to deliver photovoltaic cells with high efficiency. Mostly, the ZnO thin films are preferred as a window layer in the fabrication of solar cell because of their high transparency and wide bandgap [11]. Sulphur vacancies cause changes from stoichiometry amid its development, consequently, the quality of the surface relies upon the technique utilized and the films must be free from defects [12].…”