Although laravel is magic at times, it only works if you stick the the default configuration and conventions.
You can place your controllers anywhere (heck, even load from a database and eval them) but you have to change the configuration accordingly.
I suspect you have the wrong namespace configured in RouteServiceProvider. By default it is App\Http\Controllers.
Changing default folder
If all your controllers will be in the same folder, change it to App\Student\Controllers and forget about it should work.
class RouteServiceProvider extends ServiceProvider { // ... protected $namespace = 'App\Student\Controllers'; // ... } Multiple modules
If you want to have multiple modules, then change your RotueServiceProvider namespace config to App and in route files use Student\Controllers\StudentController@list
class RouteServiceProvider extends ServiceProvider { // ... protected $namespace = 'App'; // ... } Route::get('/list', 'Student\Controllers\StudentController@list');