High-Efficiency Silicon Heterojunction Solar Cells by HWCVD

T. H. Wang, E. Iwaniczko, M. R. Page, Qi Wang, Y. Xu, Y. Yan, D. Levi, L. Roybal, R. Bauer, H. M. Branz

Research output: Contribution to conferencePaperpeer-review

17 Scopus Citations


We report progresses in the development of silicon heterojunction (SHJ) solar cells by hot-wire chemical vapor deposition (HWCVD). A confirmed 18.2% efficiency on a p-type textured wafer has been achieved based on improvements in surface passivation by a-Si:H emitter and back contact as well as in fill factor. The primary objective of high open-circuit voltage (Voc) is achieved by front a-Si:H/c-Si heterojunction optimization, by replacing a conventional Al-alloyed or P-diffused back-surface field with a back c-Si/a-Si:H heterojunction, and by maintaining excellent surface passivation on textured silicon wafers. We first obtain a Voc of 652 mV with a front a-Si:H(n/i) heterojunction emitter on p-type solar cells with an Al back-surface-field (BSF) contact. The high-temperature AI-BSF is then successfully replaced by low-temperature HWCVD-deposited a-Si:H(i/p) layers as the back contact. Lifetime measurement shows the surface recombination velocity (SRV) is reduced to -15 cm/sec. A higher Voc of 676 mV is obtained with an a-Si:H(n/i) front-emitter and a-Si:H(i/p) back-contact double-heterojunction SHJ solar cell structure, indicating superior back-surface passivation of the textured p-wafer. On n-type silicon wafers, we use an a-Si:H(p/i) front emitter and an a-Si:H(i/n) back contact, to achieve a V oc of 711 mV, the highest voltage obtained by the HWCVD technique so far. Good fill factors are also obtained using the amorphous-phase materials as the back contacts. S-shaped I-V curves are observed if doping cross-contamination are present among different a-Si:H layers or doping level is not enough in the TCO-contacting p-type a-Si:H layer.

Original languageAmerican English
Number of pages4
StatePublished - 2006
Event2006 IEEE 4th World Conference on Photovoltaic Energy Conversion, WCPEC-4 - Waikoloa, HI, United States
Duration: 7 May 200612 May 2006


Conference2006 IEEE 4th World Conference on Photovoltaic Energy Conversion, WCPEC-4
Country/TerritoryUnited States
CityWaikoloa, HI

NREL Publication Number

  • NREL/CP-520-39272


Dive into the research topics of 'High-Efficiency Silicon Heterojunction Solar Cells by HWCVD'. Together they form a unique fingerprint.

Cite this