Fresh graduate? When you want to resign, do talk to your report manager first then ask him/her who you should be included for your resignation letter.
Please don't just send out a email without talk to anyone。

if your manager is not around, then you can try to skype him or send him a email that you would like to resign with your reason.
A professional manager definitely will try to understand why you want to leave the company and what he/she can do for you to stay. To respect report manager, I always think that report manager should be the first person to know.

In my opinion, reputation is important so better follow the normal procedure. Tender, serve notice period then say bye bye.
I was in a 2 years stupid bond as well and it really terrible experience but I decided to take it as a lesson. Anyway, the terrible experience was great experience because handle a full of shit project and dealing with tough customers increase my tolerance level to the max. Hahaha..