Photoluminescence from Ion Implanted CdTe Crystals

2005 ◽  
Vol 865 ◽  
Author(s):  
Xiangxin Liu ◽  
A. D. Compaan

AbstractWe have studied the photoluminescence of CdTe crystals doped with two elements, Cu and Cl, that are frequently used in CdTe-based solar cells. Ions were implanted into high-quality single crystals of CdTe at the Toledo Heavy Ion Accelerator Lab in our Department. We used a standard Monte Carlo simulation program to plan an implant dosage at three different energies. The lattice damage was removed by thermal annealing in an inert atmosphere using a proximity cap to avoid surface deterioration. The PL spectra at 40K were obtained at 488 nm or 752nm to match the absorption depth with the implant profile. Using implant densities typically of 1016, 1017, and 1018 /cm3, and laser excitation power densities ranging over several orders of magnitude, we have identified band-to-band transitions, free-to-bound transitions, bound-exciton lines, and donor-acceptor pair transitions related to these species.

Author(s):  
M. W. Bench ◽  
I. M. Robertson ◽  
M. A. Kirk

Transmission electron microscopy experiments have been performed to investigate the lattice damage created by heavy-ion bombardments in GaAs. These experiments were undertaken to provide additional insight into the mechanisms by which individual amorphous zones and eventually amorphous layers are created. To understand these mechanisms, the structure of the defects created as a function of material, irradiating ion, dose, dose rate, and implantation tenperature have been studied using TEM. Also, the recovery of the crystalline structure by annealing has been investigated.These experiments were performed at the High-Voltage Electron Microscope - Ion Accelerator Facility at Argonne National Laboratory. This facility consists of an HVEM which has been interfaced with two ion accelerators. This coupling, plus the availability of several specimen stages permits ion irradiations to be performed in the specimen chamber of the microscope at controlled temperatures from 10 to 1000 K.


1991 ◽  
Vol 235 ◽  
Author(s):  
Tsutomu Iida ◽  
Yunosuke Makita ◽  
Shigeru Niki ◽  
Akimasa Yamada ◽  
Hisao Asakura ◽  
...  

ABSTRACTPhotoluminescence (PL) measurements have been carried out as a function of temperature and of excitation power on heavily magnesium (Mg) implanted ultra-pure indium phosphide (InP) with a dose concentration, [Mg], ranging from l×lO15cm-3 to 3×1020cm−3. Several undefined emissions have been observed; a strong emission, Z, emerges near the band-acceptor emission for [Mg]= 3×1020cm−3 and two novel emissions, Y1 and Y3 appear below the energy of donor-acceptor pair emission for [Mg] smaller than 3×1018cm−3. In order to obtain more explanation on such emission, temperature and excitation power dependence of the emissions were investigated. Temperature dependent PL experiments revealed that Z is composed of three emissions named ZA, ZBand ZC. Measured activation energies suggest Z represents a pair type transition associated with Mg acceptors. While, Y1 and Y3 emissions are attributed to donor-acceptor type transition because of a significant blue-shift with increasing excitation power.


2003 ◽  
Vol 798 ◽  
Author(s):  
Zhe Chuan Feng ◽  
Adam M. Payne ◽  
David Nicol ◽  
Paul D. Helm ◽  
Ian Ferguson ◽  
...  

ABSTRACTThis work initiates an investigation of molecular co-doping to produce p-type centers in (Ga,Al)N with ionization energies lower than Mg. Dopant complexes can be formed between a doubly ionized acceptor such as (Cu, Li or Ag) and a singly ionized donor (silicon). Ion implantation of Cu, Li and Ag into silicon doped GaN films grown by Metalorganic Chemical Vapor Deposition (MOCVD) has been performed. Secondary ion mass spectroscopy (SIMS) data confirmed the simulated depth profile. High resolution X-ray diffraction and Raman spectroscopy were used to characterize the crystalline damage and subsequent recovery upon anneal. A complete recovery was observed after high temperature (700–900°C) annealing. Low temperature (6K) photoluminescence (PL) for Cu-implanted GaN showed bands identified with crystalline lattice damage due to the Cu-implantation. The annealed samples showed recovery of standard crystalline GaN features. Additional donor-acceptor pair features are observed below 3.35 eV indicating the existence of an acceptor state.


Author(s):  
F. J. Sánchez ◽  
F. Calle ◽  
M.A. Sanchez-Garcia ◽  
E. Calleja ◽  
E. Muñoz ◽  
...  

Low temperature photoluminescence spectra of Be-doped layers grown on Si (111) by molecular beam epitaxy have been analyzed. Emissions at 3.466 eV and 3.384 eV, and a broad band centered at 2.4-2.5 eV are observed. Their evolution with temperature and excitation power, and time resolved PL measurements ascribe an excitonic character for the luminescence at 3.466 eV, whereas the emission at 3.384 eV is associated with a donor-acceptor pair transition. This recombination involves residual donors and Be-related acceptors, which are located around 90meV above the valence band, confirming Be as the shallowest acceptor reported in GaN. The intensity of the band at 2.4-2.5 eV increases with the Be content. This emission involves a band of deep acceptors generated by Be complex defects, as suggested by the parameter g = 2.008 ± 0.003 obtained by photoluminescence-detected electron paramagnetic resonance.


1989 ◽  
Vol 162 ◽  
Author(s):  
J. A. Freitas ◽  
S. G. Bishop

ABSTRACTThe temperature and excitation intensity dependence of photoluminescence (PL) spectra have been studied in thin films of SiC grown by chemical vapor deposition on Si (100) substrates. The low power PL spectra from all samples exhibited a donor-acceptor pair PL band which involves a previously undetected deep acceptor whose binding energy is approximately 470 meV. This deep acceptor is found in every sample studied independent of growth reactor, suggesting the possibility that this background acceptor is at least partially responsible for the high compensation observed in Hall effect studies of undoped films of cubic SiC.


1996 ◽  
Vol 14 (3) ◽  
pp. 347-368 ◽  
Author(s):  
V.Yu. Baranov ◽  
K.N. Makarov ◽  
V.C. Roerich ◽  
Yu.A. Satov ◽  
A.N. Starostin ◽  
...  

The results of lead ion generation with charge state from Pb10+ to Pb35+ from laser-heated plasma are presented. CO2 lasers producing 10.6-μm wavelength radiation at power densities in the range 4.1011-6.1014 W/cm2 in TBKI and CERN were used. Results of detailed numerical simulations presented in the paper are in good agreement with the experimental data. Work done in collaboration with CERN, ITEP, and TBKI was aimed at the specification of requirements for a laser system that will be able to drive an ion source for the hadron collider (LHC) at CERN.


1991 ◽  
Vol 240 ◽  
Author(s):  
A. G. Choo ◽  
H. E. Jackson ◽  
P. Chen ◽  
A. J. Steckl ◽  
V. Gupta ◽  
...  

ABSTRACTLow temperature photoluminescence spectra have been used to characterize conventional ion beam (CIB) and focused ion beam (FIB) implanted superlattices. The excitation dependence of the single scan FIB is found to be significantly different from CIB and multiple scan FIB implantations which are similar. The peak position of the donor-acceptor transition is observed to change to higher energies significantly slower with excitation intensity for the single scan FIB case when compared to the multiple scan FIB and CIB cases. Simple models to describe these effects are briefly discussed.


Author(s):  
R. Freitag ◽  
K. Thonke ◽  
R. Sauer ◽  
D. G. Ebling ◽  
L. Steinke

We report on the time-resolved luminescence of the defect-related violet band from undoped AlN epitaxial layers grown on sapphire and SiC. For both measurements in photoluminescence and in cathodoluminescence a decay of algebraic nature at long times is observed. This is typical for donor-acceptor pair transitions. We compare the behavior of this band to that of the generically yellow luminescence of GaN.


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