Strain modulating electronic band gaps and SQ efficiencies of semiconductor 2D PdQ2 (Q = S, Se) monolayer
Dhara Raval, Sanjeev K. Gupta, P. N. Gajjar, Rajeev Ahuja
Abstract
Abstract We studied the physical, electronic transport and optical properties of a unique pentagonal PdQ 2 (Q = S, Se) monolayers. The dynamic stability of 2Dwrinkle like-PdQ 2 is proven by positive phonon frequencies in the phonon dispersion curve. The optimized structural parameters of wrinkled pentagonal PdQ 2 are in good agreement with the available experimental results. The ultimate tensile strength (UTHS) was calculated and found that, penta-PdS 2 monolayer can withstand up to 16% (18%) strain along x ( y ) direction with 3.44 GPa (3.43 GPa). While, penta-PdSe 2 monolayer can withstand up to 17% (19%) strain along x ( y ) dirrection with 3.46 GPa (3.40 GPa). It is found that, the penta-PdQ 2 monolayers has the semiconducting behavior with indirect band gap of 0.94 and 1.26 eV for 2D-PdS 2 and 2D-PdSe 2 , respectively. More interestingly, at room temperacture, the hole mobilty (electron mobility) obtained for 2D-PdS 2 and PdSe 2 are 67.43 (258.06) cm 2 V −1 s −1 and 1518.81 (442.49) cm 2 V −1 s −1 , respectively. In addition, I-V characteristics of PdSe 2 monolayer show strong negative differential conductance (NDC) region near the 3.57 V. The Shockly-Queisser (SQ) effeciency prameters of PdQ 2 monolayers are also explored and the highest SQ efficeinciy obtained for PdS 2 is 33.93% at −5% strain and for PdSe 2 is 33.94% at −2% strain. The penta-PdQ 2 exhibits high optical absorption intensity in the UV region, up to 4.04 × 10 5 (for PdS 2 ) and 5.28 × 10 5 (for PdSe 2 ), which is suitable for applications in optoelectronic devices. Thus, the ultrathin PdQ 2 monolayers could be potential material for next-generation solar-cell applications and high performance nanodevices.