ensaf mohammed al-khalqi, muhammad azmi abdul hamid, naif h. al-hardan, lim kar keng.  (2021).  highly sensitive magnesium-doped zno nanorod ph sensors based on electrolyte-insulator-semiconductor (eis) sensors.  - sensors.  1-16. 

naif h. al-hardan, muhammad azmi abdul hamid, mohd firdaus-raih, lim kar keng, ensaf mohammed al-khalqi, azman jalar.  (2021).  calcium ion-selective electrode based on the facile synthesis of cuo over cu wires.  - journal of materials science: materials in electronics.  1-12. 

naif h. al-hardan, muhammad azmi abdul hamid, lim kar keng, ensaf mohammed al-khalqi, azman jalar, wee siong chiu.  (2021).  low-cost fabrication of a ph sensor based on writing directly over parchment-type paper with pencil.  - journal of materials science: materials in electronics.  9431-9439.