Samsung Electronics, facing slower demand for smartphones, will release a new device with a larger 5.2-inch screen and sharper display than the current Galaxy S4, a source said. The new phone, with an improved battery and camera, will be released about the same time as an upgraded Galaxy Gear smart watch, the source said. Samsung might start selling the new phone for less than previous models in the S series, another source said. Samsung is adding features to the latest version of its most-popular device as it tries to fight stalling growth for premium smartphones, new models from Apple, and a plethora of Chinese competitors selling devices for as little as US$100. The world's biggest smartphone maker is releasing its new phone, which may be called the S5, after sales of the predecessor S4 unveiled last year fell short of analyst estimates. "For me, better specs don't cut it," Gartner analyst Roberta Cozza said. "They need to find a way to get users to pick the Samsung brand across different types of devices to better compete with Apple." Asia's biggest technology company plans to debut the device at the Mobile World Congress in Barcelona next week. Samsung studied the possibility of using eye-scanner technology in the new phone, Lee Young-hee, an executive vice-president of the company's mobile business, said last month. Sales of the company's marquee S4 slowed after the release in September last year of Apple's iPhone 5s, which includes a fingerprint-identity sensor. Samsung, which sells about one of every four mobile phones globally, saw its shipments and market share fall in the fourth quarter of last year compared with the same quarter in 2012, according to IDC data. Samsung shipped 112 million mobile phones in the quarter, against 113.6 million units a year earlier. Its shipment market share declined to 22.9 per cent in the fourth quarter from 23.5 per cent. Apple sold 51 million iPhones in the December quarter. Last month, it started selling phones through China Mobile, the world's largest carrier with 767 million subscribers. Lower sales of Samsung's marquee device contributed to its slowest profit growth since 2011 in the fourth quarter of last year, with net income rising 5.4 per cent to 7.22 trillion won (HK$52.7 billion). Operating income at the mobile unit, the company's biggest profit driver, was 5.47 trillion won, little changed from a year earlier.