BISMILLAH
According to the most correct opinion, it is not essential to have wudhu for sujood al-tilawah (The Prostration of Recitation), and there is no salam (Assalamu'alaikum) or takbir (Allahu Akbar) when coming up from it.
It is prescribed to say takbir (Allahu Akbar) when prostrating, because evidence to that effect is proven in the hadeeth of Ibn ‘Umar radhiAllahu‘anhu who said, “The Messenger of Allah (salAllahu ‘alayhi wa sallam) used to recite Qur’an to us, and if he reached an ayah where a sajdah (prostration) was prescribed, he would say takber (Allahu Akbar) and prostrate and we would do likewise.” (Reported by Ahmad, 2/17; al-Bukhaari, 2/33,34; Muslim, 1/405, no. 575).
But if the sujood al-tilawah (The Prostration of Recitation), is done during prayer, then it is obligatory to say takbir (Allahu Akbar) when going down and when coming up, because the Prophet (PBUH) used to do that in every movement of the prayer, and he said:
“Pray as you have seen me praying.” [Bukhari]
The same dhikir and du’as are prescribed in sujood al-tilawah (The Prostration of Recitation) as in the prostration during prayer, because of the general meaning of the ahadeeth concerning that. Among these du’as are:
Allahumma laka sajadtu wa bika aamantu wa laka aslamtu, sajada wajhi lilladhi khalaqahu wa sawwarahu wa shaqqa sam’ahu wa basarahu bi hawlihi wa quwwatihi, tabaarak Allahu ahsan al-khaliqeen
“O Allah, to You I have prostrated, and in You I have believed, and to You I have submitted. You are my Lord; my face has prostrated to the One Who gave it hearing and sight. Blessed is Allah the best of Creators.” [Muslim]
The Prophet (PBUH) used to say this dhikr during the prostration of prayer.
We have mentioned above that it is prescribed to say the same in sujood al-tilawah (The Prostration of Recitation) as in the prostration in prayer. It was narrated that the Prophet used to make du’a when he did sujood al-tilawah, and he would say:
اللَّهُمَّ اكْتُبْ لِي بِهَا عِنْدَكَ أَجْرًا ، وَضَعْ عَنِّي بِهَا وِزْرًا ، وَاجْعَلْهَا لِي عِنْدَكَ ذُخْرًا ، وَتَقَبَّلْهَا مِنِّي كَمَا تَقَبَّلْتَهَا مِنْ عَبْدِكَ دَاوُدَ
Allahumma aktub li biha ‘indaka ajran wa da’ ‘anni biha wizran waj’alha li ‘indaka dukhran wa taqabbalha minni kama taqabbaltaha min ‘abdika Daw’oud
“O Allah, record for me a reward for this (prostration), and remove from me a sin. Save it for me and accept it from me just as You accepted it from Your slave Daw’oud.” [at-Tirmidhi]
What is obligatory is to say, “Subhana Rabbiy al-A’laa” (Glory be to my Lord Most High), as is obligatory during the prostration of prayer. Any additional du’a or dhikr is mustahabb.
Sujood al-tilawah, (The Prostration of Recitation) whether during prayer or outside of it, is Sunnah, not obligatory, because evidence to that effect was narrated from the Prophet (PBUH), in the hadeeth of Zayd ibn Thaabit and in the hadeeth of ‘Umar (may Allah be pleased with him).
Majmul’ Fataawa wa Maqaalaat Samaahat al-Sheikh Ibn Baaz, 11/406.