Investigation of efficiency limiting defects and rapid thermal processing of MOCVD grown CdTe solar cells

Conference · Thu Jun 30 04:00:00 EDT 1994 · AIP Conference Proceedings (American Institute of Physics); (United States)

OSTI ID:7258249

Rohatgi, A; Chou, H C; Kamra, S; Bhat, A K ^[1]

---

1. School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States)

CdTe solar cells were fabricated by depositing CdTe films on CdS/SnO[sub 2]/glass substrates using metalorganic chemical vapor deposition (MOCVD) with varying Te/Cd mole ratio in the growth ambient. Auger electron spectroscopy (AES) revealed a high degree of atomic interdiffusion at the CdS/CdTe interface when the CdTe films were grown in the Te-rich conditions. The open-circuit voltage of 780 mV and cell efficiency of 11.9% were found to be the highest for the Te-rich growth ambient, suggesting that the enhanced interdiffusion in these cells leads to the gradual transition from CdS to CdTe and fewer interface states. The high effective life-time of the charge carriers in the bulk material, measured by time-resolved photoluminescence, also supports the hypothesis of reduced defect density in the CdTe cells grown in the Te-rich ambient. In order to eliminate possible Cl-related defects in CdTe, Rapid Thermal Processing (RTP) of CdS/CdTe films was done to achieve grain regrowth without the use of CdCl[sub 2] as a fluxing agent. A cell efficiency of 10.7% was recorded using RTP. Finally, a set of experiments and some model simulations were performed to determine losses due to absorption and reflection in CdS/CdTe solar cells as a function of the CdS layer thickness.

• OSTI ID: 7258249
• Report Number(s): CONF-9310273--
• Conference Information: Journal Name: AIP Conference Proceedings (American Institute of Physics); (United States) Journal Volume: 306:1
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
140501* -- Solar Energy Conversion-- Photovoltaic Conversion
ANNEALING
ANTIREFLECTION COATINGS
CADMIUM COMPOUNDS
CADMIUM SULFIDES
CADMIUM TELLURIDE SOLAR CELLS
CHALCOGENIDES
CHEMICAL COATING
CHEMICAL VAPOR DEPOSITION
COATINGS
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
DEPOSITION
DIFFUSION
DIRECT ENERGY CONVERTERS
EFFICIENCY
EQUIPMENT
HEAT TREATMENTS
INORGANIC PHOSPHORS
INTERFACES
LUMINESCENCE
PHOSPHORS
PHOTOELECTRIC CELLS
PHOTOLUMINESCENCE
PHOTOVOLTAIC CELLS
SOLAR CELLS
SOLAR EQUIPMENT
SULFIDES
SULFUR COMPOUNDS
SURFACE COATING
TEMPERATURE RANGE
TEMPERATURE RANGE 0400-1000 K