Yeah you can, but you need to pass a date anyway! So what you can do is something like this:
$dateMonthArray = explode('/', '12/2017');
$month = $dateMonthArray[0];
$year = $dateMonthArray[1];
$date = Carbon::createFromDate($year, $month, 1);
Note: You can leave the day parameter (the third one) off, but than it will pick the current day. Just make sure you know that because it might give you unexpected results.
You can also reset the time and date if you wish to the start day of the month.
$date = Carbon::createFromDate($year, $month)->startOfMonth();