Javascript Promise using Then() but Function returns Null

Question

Function checks if a technology is save in a mongo DB and if it is saved, the technology object is returned, if it is not saved, a new technology object is to be created and then returned. but when the function is called, the return value is null

function saveTechnology(technology) {
        //check if technology is already in database
        Technology.findOne({name: technology}).then(foundTechnology => {
            if(foundTechnology){
                return foundTechnology
            }else{
                new Technology({
                    name: technology
                }).save((err, newTechnology) => {
                    if(err){
        
                    }else{
                        return newTechnology
                    }
                });
            }
        });
    }