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Title: Electrical and photovoltaic properties of CdTe/ZnTe n-i-p junctions grown by molecular beam epitaxy

Preliminary studies have been performed on photoelectrical properties of CdTe/ZnTe n-i-p junctions grown using the molecular beam epitaxy technique. Photovoltaic properties of the cells have been investigated by the measurements of current-voltage (I-V) characteristics under 1-sun illumination. I-V characteristics yield efficiencies of the cells varying from 3.4% to 4.9%. The low efficiency can be due to the presence of electrically active defects. In order to study the origin of defects in CdTe/ZnTe photovoltaic junctions, space charge techniques (C-V and deep level transient spectroscopy (DLTS)) have been applied. From the C-V measurements, a doping profile was calculated confirming charge accumulation in the i-CdTe layer. The results of the DLTS studies revealed the presence of four traps within a temperature range from 77–420 K. Three of them with activation energies equal to 0.22 eV, 0.45 eV, and 0.78 eV have been ascribed to the hole traps present in the i-CdTe material and their possible origin has been discussed. The fourth, high-temperature DLTS peak observed at ∼350 K has been attributed to extended defects as its amplitude and temperature position depends on the value of the filling pulse width. It is assumed that the defects related to the trap are either located in the i-CdTe layer ormore » at the i-CdTe/ZnTe interface. However, it was found that the trap exhibits twofold nature: it behaves as a majority or as a minority trap, depending on the filling pulse height, which is a characteristic feature of recombination centers. This trap is presumably responsible for the low efficiency of the cells.« less
Authors:
; ; ;  [1] ; ; ; ;  [2]
  1. Institute of Physics, Wroclaw University of Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw (Poland)
  2. Institute of Physics, Polish Academy of Sciences, al. Lotnikow 32/46, 02-668 Warsaw (Poland)
Publication Date:
OSTI Identifier:
22304050
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 115; Journal Issue: 24; Other Information: (c) 2014 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ACTIVATION ENERGY; CADMIUM TELLURIDES; CRYSTAL DEFECTS; CURRENTS; DEEP LEVEL TRANSIENT SPECTROSCOPY; ELECTRIC CONDUCTIVITY; ELECTRIC CONTACTS; ELECTRIC POTENTIAL; INTERFACES; LAYERS; MOLECULAR BEAM EPITAXY; PHOTOVOLTAIC EFFECT; P-N JUNCTIONS; RECOMBINATION; SEMICONDUCTOR JUNCTIONS; SPACE CHARGE; TRAPS; ZINC TELLURIDES