| Records |
| Author |
Amini, M.N.; Saniz, R.; Lamoen, D.; Partoens, B. |
| Title |
The role of the VZn-NO-H complex in the p-type conductivity in ZnO |
Type |
A1 Journal article |
| Year |
2015 |
Publication |
Physical chemistry, chemical physics |
Abbreviated Journal |
Phys Chem Chem Phys |
| Volume |
17 |
Issue |
17 |
Pages |
5485-5489 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) |
| Abstract |
Past research efforts aiming at obtaining stable p-type ZnO have been based on complexes involving nitrogen doping. A recent experiment by (J. G. Reynolds et al., Appl. Phys. Lett., 2013, 102, 152114) demonstrated a significant ([similar]1018 cm−3) p-type behavior in N-doped ZnO films after appropriate annealing. The p-type conductivity was attributed to a VZnNOH shallow acceptor complex, formed by a Zn vacancy (VZn), N substituting O (NO), and H interstitial (Hi). We present here a first-principles hybrid functional study of this complex compared to the one without hydrogen. Our results confirm that the VZnNOH complex acts as an acceptor in ZnO. We find that H plays an important role, because it lowers the formation energy of the complex with respect to VZnNO, a complex known to exhibit (unstable) p-type behavior. However, this additional H atom also occupies the hole level at the origin of the shallow behavior of VZnNO, leaving only two states empty higher in the band gap and making the VZnNOH complex a deep acceptor. Therefore, we conclude that the cause of the observed p-type conductivity in experiment is not the presence of the VZnNOH complex, but probably the formation of the VZnNO complex during the annealing process. |
| Address |
|
| Corporate Author |
|
Thesis |
|
| Publisher |
|
Place of Publication |
Cambridge |
Editor |
|
| Language |
|
Wos |
000349616400080 |
Publication Date |
2015-01-20 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
1463-9076;1463-9084; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
4.123 |
Times cited |
20 |
Open Access |
|
| Notes |
FWO G021614N; FWO G015013; FWO G018914N; GOA; Hercules |
Approved |
Most recent IF: 4.123; 2015 IF: 4.493 |
Call Number  |
c:irua:123218 |
Serial |
3592 |
| Permanent link to this record |
| |
|
| |
| Author |
Sarmadian, N.; Saniz, R.; Partoens, B.; Lamoen, D. |
| Title |
Ab initio study of shallow acceptors in bixbyite V2O3 |
Type |
A1 Journal article |
| Year |
2015 |
Publication |
Journal of applied physics |
Abbreviated Journal |
J Appl Phys |
| Volume |
117 |
Issue |
117 |
Pages |
015703 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) |
| Abstract |
We present the results of our study on p-type dopability of bixbyite V2O3 using the Heyd, Scuseria, and Ernzerhof hybrid functional (HSE06) within the density functional theory (DFT) formalism. We study vanadium and oxygen vacancies as intrinsic defects and substitutional Mg, Sc, and Y as extrinsic defects. We find that Mg substituting V acts as a shallow acceptor, and that oxygen vacancies are electrically neutral. Hence, we predict Mg-doped V2O3 to be a p-type conductor. Our results also show that vanadium vacancies are relatively shallow, with a binding energy of 0.14 eV, so that they might also lead to p-type conductivity. |
| Address |
|
| Corporate Author |
|
Thesis |
|
| Publisher |
American Institute of Physics |
Place of Publication |
New York, N.Y. |
Editor |
|
| Language |
|
Wos |
000347958600067 |
Publication Date |
2015-01-05 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0021-8979;1089-7550; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
2.068 |
Times cited |
3 |
Open Access |
|
| Notes |
FWO G015013; Hercules |
Approved |
Most recent IF: 2.068; 2015 IF: 2.183 |
| Call Number |
c:irua:122728 |
Serial |
35 |
| Permanent link to this record |
| |
|
| |
| Author |
Bekaert, J.; Saniz, R.; Partoens, B.; Lamoen, D. |
| Title |
First-principles study of carbon impurities in CuInSe2 and CuGaSe2, present in non-vacuum synthesis methods |
Type |
A1 Journal article |
| Year |
2015 |
Publication |
Journal of applied physics |
Abbreviated Journal |
J Appl Phys |
| Volume |
117 |
Issue |
117 |
Pages |
015104 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) |
| Abstract |
A first-principles study of the structural and electronic properties of carbon impurities in CuInSe2 and CuGaSe2 is presented. Carbon is present in organic molecules in the precursor solutions used in non-vacuum growth methods for CuInSe2 and CuGaSe2 based photovoltaic cells. These growth methods make more efficient use of material, time, and energy than traditional vacuum methods. The formation energies of several carbon impurities are calculated using the hybrid HSE06 functional. C Cu acts as a shallow donor, CIn and interstitial C yield deep donor levels in CuInSe2, while in CuGaSe2 CGa and interstitial C act as deep amphoteric defects. So, these defects reduce the majority carrier (hole) concentration in p-type CuInSe2 and CuGaSe2 by compensating the acceptor levels. The deep defects are likely to act as recombination centers for the photogenerated charge carriers and are thus detrimental for the performance of the photovoltaic cells. On the other hand, the formation energies of the carbon impurities are high, even under C-rich growth conditions. Thus, few C impurities will form in CuInSe2 and CuGaSe2 in thermodynamic equilibrium. However, the deposition of the precursor solution in non-vacuum growth methods presents conditions far from thermodynamic equilibrium. In this case, our calculations show that C impurities formed in non-equilibrium tend to segregate from CuInSe2 and CuGaSe2 by approaching thermodynamic equilibrium, e.g., via thorough annealing. |
| Address |
|
| Corporate Author |
|
Thesis |
|
| Publisher |
American Institute of Physics |
Place of Publication |
New York, N.Y. |
Editor |
|
| Language |
|
Wos |
000347958600055 |
Publication Date |
2015-01-07 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0021-8979;1089-7550; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
2.068 |
Times cited |
6 |
Open Access |
|
| Notes |
FWO G015013; Hercules |
Approved |
Most recent IF: 2.068; 2015 IF: 2.183 |
| Call Number |
c:irua:122064 |
Serial |
1215 |
| Permanent link to this record |
