TY - JOUR
T1 - Material utilisation when depositing CdTe layers by inline AP-MOCVD
AU - Barrioz, V.
AU - Kartopu, G.
AU - Irvine, S. J.C.
AU - Monir, S.
AU - Yang, X.
N1 - Funding Information:
The authors gratefully thank The Welsh Government for its financial support with the Technology Transfer Centre (TTC) project to build the research-scale inline reactor, the EPSRC for funding the PV SUPERGEN project PV21, and the Low Carbon Research Institute (LCRI) for funding the SPARC Cymru project through the European Convergence Region programme . Dr Peter Holliman from Bangor University is also acknowledged for access to and support in using the XRD and for discussion on XRD results. Scanwel Ltd. is also thanked for its continued support with the deposition equipment.
PY - 2012/9/1
Y1 - 2012/9/1
N2 - A study was undertaken to assess the efficiency of precursors usage during deposition of cadmium telluride (CdTe) layers via atmospheric pressure metal organic chemical vapour deposition (AP-MOCVD) for thin film photovoltaic solar cells. Precursors were released from a showerhead assembly normal to the glass substrate 0.7 mm thick (5×7.5 cm 2) being deposited which was kept stationary or moved under the showerhead assembly, with speed of upto 2.25 cm/min. In order to estimate the effective precursor utilisation, the weight deposit (layer) was compared against the theoretical values calculated for ideal molar supply. The layer thickness, composition, morphology, and crystallinity were also measured using profilometry, energy dispersive X-ray (EDX), scanning electron microscopy (SEM), and X-ray diffraction (XRD), respectively. It is shown that over 40% material utilisation can be achieved depending on the deposition parameters of substrate temperature and speed, partial pressure of precursors and total gas flow. The activation energy derived from an Arrhenius plot of deposition rate equals 49 kJ mol -1 and is consistent with previous reports of MOCVD CdTe using a horizontal reactor. This confirms that, despite the very different reactor geometry, the alkyl radical homolysis and reaction mechanism applies in the case of the inline injector geometry in the work presented here. These results demonstrate an alternative path to high throughput processing of CdTe thin film solar cells by inline AP-MOCVD.
AB - A study was undertaken to assess the efficiency of precursors usage during deposition of cadmium telluride (CdTe) layers via atmospheric pressure metal organic chemical vapour deposition (AP-MOCVD) for thin film photovoltaic solar cells. Precursors were released from a showerhead assembly normal to the glass substrate 0.7 mm thick (5×7.5 cm 2) being deposited which was kept stationary or moved under the showerhead assembly, with speed of upto 2.25 cm/min. In order to estimate the effective precursor utilisation, the weight deposit (layer) was compared against the theoretical values calculated for ideal molar supply. The layer thickness, composition, morphology, and crystallinity were also measured using profilometry, energy dispersive X-ray (EDX), scanning electron microscopy (SEM), and X-ray diffraction (XRD), respectively. It is shown that over 40% material utilisation can be achieved depending on the deposition parameters of substrate temperature and speed, partial pressure of precursors and total gas flow. The activation energy derived from an Arrhenius plot of deposition rate equals 49 kJ mol -1 and is consistent with previous reports of MOCVD CdTe using a horizontal reactor. This confirms that, despite the very different reactor geometry, the alkyl radical homolysis and reaction mechanism applies in the case of the inline injector geometry in the work presented here. These results demonstrate an alternative path to high throughput processing of CdTe thin film solar cells by inline AP-MOCVD.
KW - A3. Inline process
KW - A3. Metal organic chemical vapour deposition
KW - B2. Semiconducting II-VI materials
KW - B3. Solar cells
UR - http://www.scopus.com/inward/record.url?scp=84862702323&partnerID=8YFLogxK
U2 - 10.1016/j.jcrysgro.2012.05.023
DO - 10.1016/j.jcrysgro.2012.05.023
M3 - Article
AN - SCOPUS:84862702323
SN - 0022-0248
VL - 354
SP - 81
EP - 85
JO - Journal of Crystal Growth
JF - Journal of Crystal Growth
IS - 1
ER -
