Defect study in amorphous silicon/crystalline silicon solar cells by thermally stimulated capacitance

Abstract

Interface traps created by amorphous silicon (a-Si) deposition using dc magnetron sputtering or a microwave plasma-enhanced chemical vapor deposition method onto p-type crystalline silicon (c-Si) substrates in solar cell structures were studied by thermally stimulated capacitance. The trap properties (type, energy, and concentration) have been estimated as a function of various cell fabrication conditions. Plasma deposition of a-Si is seen to induce electron traps when the c-Si substrates are pretreated with hydrofluoric acid, and hole traps when a thin oxide layer is initially present on the c-Si. A strong correlation is observed between the trap activation energies when electron trapping centers are present and the corresponding photoresponse of these solar cells. Solar cells with 10% efficiency fabricated by a-Si sputtered at 64 W of power, exhibit 3×1014 cm−3 trapping centers with an activation energy of 0.44 eV.

Metastabilities in the electrical characteristics of Au‐CdMnTe Schottky contacts

“…In order to verify this hypothesis we have applied the method commonly used to distinguish between the surface and bulk states. This method comprises of the analysis of different biasing conditions on the TSCAP signal, defined as the difference in the capacitance after and before an optical pump [8]. The results of applying different bias on the TSCAP signal for the studied samples are given in Fig.…”

Fabrication and characteristics of n-Si/c-Si/p-Si heterojunction solar cells using hot-wire CVD

“…In addition, it has been reported that the interface condition, such as band offset and interface defects, significantly affects the carrier transport and photovoltaic properties of these solar cells [7][8][9]. Techniques for obtaining a high-quality interface include bandgap grading and passivation of the interface states by chemical HF etching [10], atomic hydrogen treatment [8], and deposition of an a-Si:H passivation layer [11,12].…”

17% efficiency heterostructure solar cell based on p-type crystalline silicon

“…Particular treatments of the crystalline surface have been investigated, such as wet cleaning by HF solutions [4] passivation by hydrogen [1,2], dry cleaning by plasmas of CF 4 [5] and CF 4 +O 2 [6], and the use of a microcrystalline (lc) [3], or a-Si:H [1] thin layer as a buffer layers to improve the interface with the c-Si substrate.…”