What field in computer science should I work on in my B. Tech project to get good research credentials and publish a paper?

Computer science offer a lot of fields in which you can do your project but it should be your Interest not the need of Paper which should drive you to explore these fields. followings are few in which you can work on (a) Artificial Intelligence and Machine learning. You can get idea of some interesting project from https://www.kaggle.com/competitions also there are few competition in it which can yield you a job Directly into Facebook or at least yield you million Dollar .https://www.kaggle.com/c/FacebookRecruiting   https://www.gequest.com/c/flight2-milestone (b) Hadoop and cloud computing Seeing the demand of Professional having basic Knowledge of Hadoop and Cloud computing http://www.edureka.co/blog/increasing-demand-for-hadoop-and-nosql-skills/ http://www.computerworld.com/article/2498697/business-intelligence/hadoop-skills-are-in-high-demand.html  this field should also be kept in option. (c)Game Development People generally Don't explore this field  but believe me if you have Interest,  This field also Deserve a try  http://www.gamasutra.com/view/news/221533/Game_Developer_Salary_Survey_2014_The_results_are_in.php.

Here are three rules you must follow Don't publish a crap paper in a crap journal. A good paper takes more than a year of research. Do it. Do it in a field you are interested it. If you are not interested in anything talk to your profs and find something. Don't publish for the sake of publishing. There is too much crap out there already. People are smart enough to differentiate between something substantial and crappy.