[1] Univ Malaya, Fac Sci, Low Dimens Mat Res Ctr, Dept Phys, Kuala Lumpur 50603, Malaysia
[2] Madurai Kamaraj Univ, Sch Chem, Ctr Photoelectrochem, Madurai 625021, Tamil Nadu, India
[3] Univ Putra Malaysia, Fac Sci, Dept Chem, Upm Serdang 43400, Selangor, Malaysia