An increase in the Efficiency of AlGaAs/GaAs Double Junction Solar Cell on Si substrate due to Electron Beam Treatment
- PDF / 796,270 Bytes
- 5 Pages / 595.22 x 842 pts (A4) Page_size
- 101 Downloads / 173 Views
An increase in the Efficiency of AlGaAs/GaAs Double Junction Solar Cell on Si substrate due to Electron Beam Treatment Hyo Jin Kim,∗ Chaewon Kim, Seong Min Kim and Wang Gi Kim Photonics Energy Research Center, Korea Photonics Technology Institute, Gwangju 61007, Korea (Received 8 December 2019; revised 11 April 2020; accepted 13 April 2020) We have studied the dependence of the growth of GaAs on Si substrate on the flow rate of the source for GaAs seed layer. GaAs buffer with different growth conditions of the inserted GaAs seed has been grown on Si (001) substrate by using metalorganic chemical vapor deposition (MOCVD). Structural properties of the GaAs buffer were investigated by using scanning electron microscopy (SEM) and high-resolution X-ray diffraction (HRXRD). The number of misfit dislocation in the GaAs seeds on Si substrates decreased as the growth rate and the V/III ratio of the GaAs seed were increased and decreased, respectively. Also, we have investigated the improvement in GaAs buffer due to electron beam (e-beam) treatment. The peak position for the GaAs buffer on Si reached the original peak of the GaAs substrate due to the e-beam treatment. Finally, the efficiency of an AlGaAs/GaAs double junction solar cell on a Si substrate was about 22.6%. Keywords: Solar cell, III-V semiconductor, Si substrate, Electron beam treatment, Thermal cycling annealing DOI: 10.3938/jkps.77.903
I. INTRODUCTION Epitaxial growth of GaAs on Si substrate has attracted significant attention for many years due to the possibility of unique material combinations, such as highly mismatched materials and polar-nonpolar materials [1]. The fabrication of GaAs solar cells on Si substrates has been reported since 1980 [2,3]. The combination of GaAs active layer and Si substrate may provide high-efficiency, high radiation resistant, low-weight, low-cost, and largearea solar cells. However, the dislocation between Si and GaAs is very large, being over 1 × 107 cm−3 [4] because of the lattice mismatch (4%), the difference in their thermal expansion coefficients, and the formation of antiphase domains (APDs) [4,5] concerning the epitaxy of polar semiconductors on (001) non-polar semiconductor substrates. Many techniques, such as in situ or postgrowth annealing [5], thermal cycle annealing [6], use of strained-layersuperlattice intermediate layers [7], use of impuritydoped layers [8], use of a sawtooth-patterned Si substrate [9] insertion of one monolayer of a group II element in place of Ga atoms at the GaAs/Si interface [10], and use of layered structure GaSe as a buffer layers can be used to improve the quality of the GaAs/Si epilayers [11]. Kawabe and Ueda reported that when the Si (100) substrate has an inclined angle in the [011] direction, the APD disappears during the initial growth process ∗ E-mail:
[email protected]
pISSN:0374-4884/eISSN:1976-8524
and in the Si (001) substrate [12]. On the other hand, when a buffer layer such as Ge is grown between Si and GaAs [13], a method for growing an InGaAs/GaAs or GaAsP/GaAs superlattice [13], the define ELO
Data Loading...
